{
  "title": "Angle Sum Property - Grade 9 Quadrilaterals",
  "total_questions": 100,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "What is the sum of all interior angles of a quadrilateral?", "options": {"A": "180°", "B": "360°", "C": "540°", "D": "720°"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "If three angles of a quadrilateral are 80°, 90°, and 100°, what is the fourth angle?", "options": {"A": "70°", "B": "80°", "C": "90°", "D": "100°"}, "correct_answer": "C"},
    {"id": 3, "difficulty": "easy", "question": "A quadrilateral has angles in ratio 1:2:3:4. What is the smallest angle?", "options": {"A": "36°", "B": "72°", "C": "108°", "D": "144°"}, "correct_answer": "A"},
    {"id": 4, "difficulty": "easy", "question": "What is the sum of exterior angles of a quadrilateral?", "options": {"A": "180°", "B": "360°", "C": "540°", "D": "720°"}, "correct_answer": "B"},
    {"id": 5, "difficulty": "easy", "question": "If one angle of a quadrilateral is 120°, what is the sum of the other three angles?", "options": {"A": "180°", "B": "240°", "C": "300°", "D": "360°"}, "correct_answer": "B"},
    {"id": 6, "difficulty": "easy", "question": "In a quadrilateral, angles are 70°, 80°, 110°. What is the fourth angle?", "options": {"A": "80°", "B": "90°", "C": "100°", "D": "110°"}, "correct_answer": "C"},
    {"id": 7, "difficulty": "easy", "question": "Which polygon has interior angle sum of 360°?", "options": {"A": "Triangle", "B": "Quadrilateral", "C": "Pentagon", "D": "Hexagon"}, "correct_answer": "B"},
    {"id": 8, "difficulty": "easy", "question": "If all angles of a quadrilateral are equal, what is each angle?", "options": {"A": "60°", "B": "90°", "C": "120°", "D": "180°"}, "correct_answer": "B"},
    {"id": 9, "difficulty": "easy", "question": "Three angles of quadrilateral are 85°, 95°, 110°. Fourth angle is:", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "B"},
    {"id": 10, "difficulty": "easy", "question": "What is each exterior angle of a regular quadrilateral (square)?", "options": {"A": "60°", "B": "90°", "C": "120°", "D": "180°"}, "correct_answer": "B"},
    {"id": 11, "difficulty": "easy", "question": "If quadrilateral has angles x, 2x, 3x, 4x, what is x?", "options": {"A": "30°", "B": "36°", "C": "45°", "D": "60°"}, "correct_answer": "B"},
    {"id": 12, "difficulty": "easy", "question": "Sum of opposite angles in a cyclic quadrilateral is:", "options": {"A": "90°", "B": "180°", "C": "270°", "D": "360°"}, "correct_answer": "B"},
    {"id": 13, "difficulty": "easy", "question": "If one angle of quadrilateral is right angle, sum of other three is:", "options": {"A": "180°", "B": "270°", "C": "360°", "D": "450°"}, "correct_answer": "B"},
    {"id": 14, "difficulty": "easy", "question": "Three angles are 100°, 110°, 120°. Fourth angle measures:", "options": {"A": "20°", "B": "30°", "C": "40°", "D": "50°"}, "correct_answer": "B"},
    {"id": 15, "difficulty": "easy", "question": "Each interior angle of regular quadrilateral is:", "options": {"A": "60°", "B": "90°", "C": "108°", "D": "120°"}, "correct_answer": "B"},
    {"id": 16, "difficulty": "easy", "question": "If quadrilateral has two right angles, sum of other two is:", "options": {"A": "90°", "B": "180°", "C": "270°", "D": "360°"}, "correct_answer": "B"},
    {"id": 17, "difficulty": "easy", "question": "Angles of quadrilateral are 2x, 3x, 4x, 5x. Largest angle is:", "options": {"A": "100°", "B": "120°", "C": "130°", "D": "150°"}, "correct_answer": "C"},
    {"id": 18, "difficulty": "easy", "question": "Exterior angle at each vertex of square is:", "options": {"A": "45°", "B": "90°", "C": "135°", "D": "180°"}, "correct_answer": "B"},
    {"id": 19, "difficulty": "easy", "question": "If three angles are in ratio 2:3:4 and fourth is 90°, smallest angle is:", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "D"},
    {"id": 20, "difficulty": "easy", "question": "Sum of interior angles of quadrilateral equals sum of its:", "options": {"A": "Sides", "B": "Exterior angles", "C": "Diagonals", "D": "Adjacent angles"}, "correct_answer": "B"},
    
    {"id": 21, "difficulty": "medium", "question": "In quadrilateral ABCD, ∠A = 75°, ∠B = 105°, ∠C = 85°. Find ∠D.", "options": {"A": "85°", "B": "90°", "C": "95°", "D": "100°"}, "correct_answer": "C"},
    {"id": 22, "difficulty": "medium", "question": "Three angles of quadrilateral are equal and fourth is 60°. Each equal angle is:", "options": {"A": "80°", "B": "90°", "C": "100°", "D": "110°"}, "correct_answer": "C"},
    {"id": 23, "difficulty": "medium", "question": "If angles of quadrilateral are (x-10)°, (x+20)°, (2x-20)°, (2x+10)°, find smallest angle.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 24, "difficulty": "medium", "question": "In cyclic quadrilateral ABCD, ∠A = 70°, ∠B = 110°. Find ∠C + ∠D.", "options": {"A": "180°", "B": "190°", "C": "200°", "D": "210°"}, "correct_answer": "A"},
    {"id": 25, "difficulty": "medium", "question": "If one angle of quadrilateral is 135° and other three are in ratio 2:3:4, find largest angle.", "options": {"A": "80°", "B": "90°", "C": "100°", "D": "110°"}, "correct_answer": "C"},
    {"id": 26, "difficulty": "medium", "question": "Exterior angles of quadrilateral are in ratio 1:2:3:4. Find smallest interior angle.", "options": {"A": "36°", "B": "54°", "C": "72°", "D": "108°"}, "correct_answer": "D"},
    {"id": 27, "difficulty": "medium", "question": "In quadrilateral, ∠A = ∠B = ∠C and ∠D = 120°. Find ∠A.", "options": {"A": "70°", "B": "75°", "C": "80°", "D": "85°"}, "correct_answer": "C"},
    {"id": 28, "difficulty": "medium", "question": "If three exterior angles are 70°, 80°, 90°, fourth exterior angle is:", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 29, "difficulty": "medium", "question": "Angles of quadrilateral are (3x+5)°, (4x-10)°, (2x+20)°, (5x-15)°. Find value of x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 30, "difficulty": "medium", "question": "If one interior angle is 150°, what is its corresponding exterior angle?", "options": {"A": "20°", "B": "30°", "C": "40°", "D": "50°"}, "correct_answer": "B"},
    {"id": 31, "difficulty": "medium", "question": "In quadrilateral, ∠A:∠B:∠C:∠D = 3:4:5:6. Find ∠C.", "options": {"A": "80°", "B": "90°", "C": "100°", "D": "110°"}, "correct_answer": "C"},
    {"id": 32, "difficulty": "medium", "question": "If sum of two opposite angles is 200°, sum of other two is:", "options": {"A": "140°", "B": "150°", "C": "160°", "D": "170°"}, "correct_answer": "C"},
    {"id": 33, "difficulty": "medium", "question": "Three angles are (x+15)°, (2x-20)°, (3x+5)°. Fourth is 90°. Find x.", "options": {"A": "25", "B": "30", "C": "35", "D": "40"}, "correct_answer": "A"},
    {"id": 34, "difficulty": "medium", "question": "Exterior angle at vertex A of quadrilateral is 110°. Interior ∠A is:", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "B"},
    {"id": 35, "difficulty": "medium", "question": "If quadrilateral has three acute angles, fourth angle must be:", "options": {"A": "Acute", "B": "Right", "C": "Obtuse", "D": "Reflex"}, "correct_answer": "C"},
    {"id": 36, "difficulty": "medium", "question": "Angles are (2a+10)°, (3a-20)°, (4a+30)°, (5a-40)°. Find a.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "A"},
    {"id": 37, "difficulty": "medium", "question": "If each interior angle is double its exterior angle, each interior angle is:", "options": {"A": "90°", "B": "120°", "C": "135°", "D": "150°"}, "correct_answer": "B"},
    {"id": 38, "difficulty": "medium", "question": "In quadrilateral, ∠A = 2∠B = 3∠C = 6∠D. Find ∠A.", "options": {"A": "120°", "B": "144°", "C": "160°", "D": "180°"}, "correct_answer": "B"},
    {"id": 39, "difficulty": "medium", "question": "If three exterior angles are 85°, 95°, 105°, fourth is:", "options": {"A": "65°", "B": "70°", "C": "75°", "D": "80°"}, "correct_answer": "C"},
    {"id": 40, "difficulty": "medium", "question": "Sum of two adjacent angles is 150°. Sum of other two is:", "options": {"A": "180°", "B": "200°", "C": "210°", "D": "220°"}, "correct_answer": "C"},
    {"id": 41, "difficulty": "medium", "question": "If interior angle is 5/4 times its exterior angle, interior angle is:", "options": {"A": "90°", "B": "100°", "C": "110°", "D": "120°"}, "correct_answer": "B"},
    {"id": 42, "difficulty": "medium", "question": "Three angles are in AP with common difference 10°. If largest is 110°, smallest is:", "options": {"A": "70°", "B": "80°", "C": "90°", "D": "100°"}, "correct_answer": "B"},
    {"id": 43, "difficulty": "medium", "question": "If quadrilateral has three right angles, fourth angle is:", "options": {"A": "Acute", "B": "Right", "C": "Obtuse", "D": "Straight"}, "correct_answer": "B"},
    {"id": 44, "difficulty": "medium", "question": "Exterior angles are (x+5)°, (2x-10)°, (3x+15)°, (4x-20)°. Find x.", "options": {"A": "25", "B": "30", "C": "35", "D": "40"}, "correct_answer": "C"},
    {"id": 45, "difficulty": "medium", "question": "If each angle of quadrilateral is less than 180°, maximum number of obtuse angles possible is:", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "C"},
    {"id": 46, "difficulty": "medium", "question": "Angles are 2x, 3x, 4x, and (360-9x). Find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "C"},
    {"id": 47, "difficulty": "medium", "question": "If one angle is 40° more than smallest and largest is 60° more than smallest, and sum of smallest and largest is 160°, find all angles.", "options": {"A": "40°,80°,100°,140°", "B": "50°,90°,100°,120°", "C": "60°,100°,110°,90°", "D": "70°,110°,120°,60°"}, "correct_answer": "B"},
    {"id": 48, "difficulty": "medium", "question": "In quadrilateral, ∠A = 60°, ∠B = 120°, ∠C = 70°. Find ∠D.", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "B"},
    {"id": 49, "difficulty": "medium", "question": "If exterior angles are in ratio 1:2:3:6, largest interior angle is:", "options": {"A": "120°", "B": "135°", "C": "150°", "D": "165°"}, "correct_answer": "C"},
    {"id": 50, "difficulty": "medium", "question": "Three angles are (x+30)°, (2x-20)°, (3x+10)°. Fourth is 90°. Find largest angle.", "options": {"A": "110°", "B": "120°", "C": "130°", "D": "140°"}, "correct_answer": "C"},
    {"id": 51, "difficulty": "medium", "question": "If sum of three angles is 320°, fourth angle is:", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    {"id": 52, "difficulty": "medium", "question": "Angles are (3k+5)°, (4k-10)°, (5k+15)°, (6k-20)°. Find k.", "options": {"A": "10", "B": "15", "C": "20", "D": "25"}, "correct_answer": "C"},
    {"id": 53, "difficulty": "medium", "question": "If interior angle:exterior angle = 5:4, interior angle is:", "options": {"A": "80°", "B": "100°", "C": "120°", "D": "140°"}, "correct_answer": "B"},
    {"id": 54, "difficulty": "medium", "question": "In quadrilateral, ∠A = ∠B, ∠C = ∠D, and ∠A + ∠C = 180°. If ∠A = 70°, find ∠C.", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "B"},
    {"id": 55, "difficulty": "medium", "question": "If three angles are 110°, 120°, 130°, fourth angle is:", "options": {"A": "0°", "B": "10°", "C": "20°", "D": "30°"}, "correct_answer": "A"},
    {"id": 56, "difficulty": "medium", "question": "Maximum number of acute angles in convex quadrilateral is:", "options": {"A": "1", "B": "2", "C": "3", "D": "4"}, "correct_answer": "C"},
    {"id": 57, "difficulty": "medium", "question": "If ∠A = 95°, ∠B = 85°, ∠C = 105°, then ∠D = ?", "options": {"A": "65°", "B": "75°", "C": "85°", "D": "95°"}, "correct_answer": "B"},
    {"id": 58, "difficulty": "medium", "question": "Angles are in ratio 5:6:7:8. Difference between largest and smallest is:", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    {"id": 59, "difficulty": "medium", "question": "If one angle is 30° less than twice the smallest, another is 20° more than smallest, third is 50° more than smallest, and sum is 360°, find smallest.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 60, "difficulty": "medium", "question": "Exterior angles are 70°, 80°, 90°, x. Interior angle corresponding to x is:", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 61, "difficulty": "medium", "question": "If angles are (2x+10)°, (3x-20)°, (4x+30)°, (5x-40)°, find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "A"},
    {"id": 62, "difficulty": "medium", "question": "In cyclic quadrilateral, opposite angles are (3x+10)° and (5x-30)°. Find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 63, "difficulty": "medium", "question": "If interior angle is 20° more than twice its exterior angle, interior angle is:", "options": {"A": "100°", "B": "120°", "C": "140°", "D": "160°"}, "correct_answer": "C"},
    {"id": 64, "difficulty": "medium", "question": "Three angles are equal. Fourth is 60°. Each equal angle is:", "options": {"A": "90°", "B": "95°", "C": "100°", "D": "105°"}, "correct_answer": "C"},
    {"id": 65, "difficulty": "medium", "question": "If ∠A = 100°, ∠B = 80°, ∠C = 95°, then ∠D = ?", "options": {"A": "75°", "B": "80°", "C": "85°", "D": "90°"}, "correct_answer": "C"},
    {"id": 66, "difficulty": "medium", "question": "Angles are (x+20)°, (2x-10)°, (3x+5)°, (4x-15)°. Find smallest angle.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 67, "difficulty": "medium", "question": "If sum of two adjacent angles is 180°, quadrilateral is:", "options": {"A": "Cyclic", "B": "Parallelogram", "C": "Trapezium", "D": "Kite"}, "correct_answer": "B"},
    {"id": 68, "difficulty": "medium", "question": "Exterior angles are in AP with common difference 10°. Largest exterior is 110°. Smallest interior is:", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "D"},
    {"id": 69, "difficulty": "medium", "question": "If three angles are 85°, 95°, 100°, fourth is:", "options": {"A": "70°", "B": "75°", "C": "80°", "D": "85°"}, "correct_answer": "C"},
    {"id": 70, "difficulty": "medium", "question": "Angles are 2:3:4:5. Second largest angle is:", "options": {"A": "80°", "B": "90°", "C": "100°", "D": "110°"}, "correct_answer": "C"},
    {"id": 71, "difficulty": "medium", "question": "If ∠A = 70°, ∠B = 110°, ∠C = 60°, then ∠D = ?", "options": {"A": "110°", "B": "115°", "C": "120°", "D": "125°"}, "correct_answer": "C"},
    {"id": 72, "difficulty": "medium", "question": "In quadrilateral, ∠A = 2∠B, ∠C = 3∠B, ∠D = 4∠B. Find ∠B.", "options": {"A": "30°", "B": "36°", "C": "40°", "D": "45°"}, "correct_answer": "B"},
    {"id": 73, "difficulty": "medium", "question": "If exterior angles are 65°, 75°, 85°, then fourth is:", "options": {"A": "115°", "B": "125°", "C": "135°", "D": "145°"}, "correct_answer": "C"},
    {"id": 74, "difficulty": "medium", "question": "Three angles are (x+10)°, (2x-20)°, (3x+30)°. Fourth is 90°. Find x.", "options": {"A": "25", "B": "30", "C": "35", "D": "40"}, "correct_answer": "A"},
    {"id": 75, "difficulty": "medium", "question": "If one angle is 150°, sum of its adjacent angles is:", "options": {"A": "150°", "B": "180°", "C": "210°", "D": "240°"}, "correct_answer": "C"},
    {"id": 76, "difficulty": "medium", "question": "Angles are (3a+5)°, (4a-10)°, (5a+15)°, (6a-20)°. Find a.", "options": {"A": "15", "B": "20", "C": "25", "D": "30"}, "correct_answer": "B"},
    {"id": 77, "difficulty": "medium", "question": "If quadrilateral has two right angles and one angle 60°, fourth angle is:", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 78, "difficulty": "medium", "question": "Exterior angles are in ratio 2:3:4:5. Largest interior angle is:", "options": {"A": "120°", "B": "130°", "C": "140°", "D": "150°"}, "correct_answer": "D"},
    {"id": 79, "difficulty": "medium", "question": "If ∠A = 80°, ∠B = 100°, ∠C = 90°, then ∠D = ?", "options": {"A": "80°", "B": "85°", "C": "90°", "D": "95°"}, "correct_answer": "C"},
    {"id": 80, "difficulty": "medium", "question": "Angles are x, 2x, 3x, 4x. Sum of smallest and largest is:", "options": {"A": "150°", "B": "160°", "C": "170°", "D": "180°"}, "correct_answer": "D"},
    
    {"id": 81, "difficulty": "hard", "question": "In quadrilateral ABCD, ∠A:∠B = 2:3, ∠B:∠C = 3:4, ∠C:∠D = 4:5. Find ∠A.", "options": {"A": "48°", "B": "60°", "C": "72°", "D": "84°"}, "correct_answer": "A"},
    {"id": 82, "difficulty": "hard", "question": "If interior angles of quadrilateral are (4x+5)°, (5x-5)°, (6x+5)°, (7x-5)°, find difference between largest and smallest.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "C"},
    {"id": 83, "difficulty": "hard", "question": "Exterior angles of quadrilateral are in AP. If smallest exterior is 30°, find largest interior angle.", "options": {"A": "120°", "B": "130°", "C": "140°", "D": "150°"}, "correct_answer": "D"},
    {"id": 84, "difficulty": "hard", "question": "In cyclic quadrilateral, angles are (2x-10)°, (3x+20)°, (4x-30)°, (5x+40)°. Find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "A"},
    {"id": 85, "difficulty": "hard", "question": "If sum of two opposite angles is 220° and other two are in ratio 3:7, find smaller of these two.", "options": {"A": "42°", "B": "48°", "C": "54°", "D": "60°"}, "correct_answer": "A"},
    {"id": 86, "difficulty": "hard", "question": "Angles are such that second is twice first, third is three times first, fourth is four times first. Find all angles.", "options": {"A": "24°,48°,72°,96°", "B": "30°,60°,90°,120°", "C": "36°,72°,108°,144°", "D": "40°,80°,120°,160°"}, "correct_answer": "C"},
    {"id": 87, "difficulty": "hard", "question": "If exterior angles are (x+10)°, (2x-20)°, (3x+30)°, (4x-40)° and sum of two largest interiors is 240°, find smallest exterior.", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    {"id": 88, "difficulty": "hard", "question": "In quadrilateral, ∠A = ∠B + ∠C, ∠B = ∠C + ∠D, and ∠C = 60°. Find ∠A.", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 89, "difficulty": "hard", "question": "If angles are (3k-10)°, (4k+5)°, (5k-15)°, (6k+20)° and one angle is 135°, find k.", "options": {"A": "15", "B": "20", "C": "25", "D": "30"}, "correct_answer": "B"},
    {"id": 90, "difficulty": "hard", "question": "Exterior angles are in ratio 1:3:5:7. Find second smallest interior angle.", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 91, "difficulty": "hard", "question": "In quadrilateral, ∠A = 2∠B - 10°, ∠C = 3∠B + 20°, ∠D = 4∠B - 30°. Find ∠B.", "options": {"A": "40°", "B": "45°", "C": "50°", "D": "55°"}, "correct_answer": "C"},
    {"id": 92, "difficulty": "hard", "question": "If sum of three angles is 300° and they are in ratio 3:4:5, find fourth angle.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "C"},
    {"id": 93, "difficulty": "hard", "question": "Angles are (x+2y)°, (2x-y)°, (3x+y)°, (4x-2y)°. If x=30, find y.", "options": {"A": "10", "B": "15", "C": "20", "D": "25"}, "correct_answer": "A"},
    {"id": 94, "difficulty": "hard", "question": "In cyclic quadrilateral, opposite angles differ by 40°. If one is 110°, other is:", "options": {"A": "70°", "B": "80°", "C": "90°", "D": "100°"}, "correct_answer": "A"},
    {"id": 95, "difficulty": "hard", "question": "If interior angles are (5x-10)°, (6x+5)°, (7x-15)°, (8x+20)° and largest is 140°, find smallest.", "options": {"A": "60°", "B": "65°", "C": "70°", "D": "75°"}, "correct_answer": "B"},
    {"id": 96, "difficulty": "hard", "question": "Exterior angles are such that three are 70°, 80°, 90° and corresponding interiors sum to 390°. Find fourth exterior.", "options": {"A": "100°", "B": "110°", "C": "120°", "D": "130°"}, "correct_answer": "C"},
    {"id": 97, "difficulty": "hard", "question": "In quadrilateral, ∠A = 1/2∠B, ∠C = 2/3∠D, ∠B = 3/4∠C. Find ∠D.", "options": {"A": "96°", "B": "108°", "C": "120°", "D": "132°"}, "correct_answer": "B"},
    {"id": 98, "difficulty": "hard", "question": "If angles are in AP with common difference 15° and largest is 120°, find smallest.", "options": {"A": "60°", "B": "65°", "C": "70°", "D": "75°"}, "correct_answer": "D"},
    {"id": 99, "difficulty": "hard", "question": "Exterior angles are (2a+10)°, (3a-5)°, (4a+15)°, (5a-20)°. If one interior is 130°, find a.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 100, "difficulty": "hard", "question": "In quadrilateral, sum of two adjacent angles is 180°. If one is 40° more than other and third angle is 100°, find fourth angle.", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "C"}
  ]
}