{
  "title": "Angle Sum Property of Triangle - Grade 9 CBSE",
  "total_questions": 100,
  "questions": [
    {"id": 1, "difficulty": "easy", "question": "What is the sum of angles in a triangle?", "options": {"A": "90°", "B": "180°", "C": "270°", "D": "360°"}, "correct_answer": "B"},
    {"id": 2, "difficulty": "easy", "question": "If two angles of a triangle are 60° and 70°, what is the third angle?", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 3, "difficulty": "easy", "question": "A triangle with angles 45°, 45°, 90° is called:", "options": {"A": "Equilateral", "B": "Isosceles right", "C": "Scalene", "D": "Obtuse"}, "correct_answer": "B"},
    {"id": 4, "difficulty": "easy", "question": "If all angles of a triangle are equal, each angle measures:", "options": {"A": "45°", "B": "60°", "C": "90°", "D": "120°"}, "correct_answer": "B"},
    {"id": 5, "difficulty": "easy", "question": "In a right triangle, the two acute angles are:", "options": {"A": "Supplementary", "B": "Complementary", "C": "Equal", "D": "Right angles"}, "correct_answer": "B"},
    {"id": 6, "difficulty": "easy", "question": "If one angle of a triangle is 90°, the sum of other two angles is:", "options": {"A": "45°", "B": "90°", "C": "180°", "D": "270°"}, "correct_answer": "B"},
    {"id": 7, "difficulty": "easy", "question": "An equilateral triangle has each angle equal to:", "options": {"A": "45°", "B": "60°", "C": "90°", "D": "120°"}, "correct_answer": "B"},
    {"id": 8, "difficulty": "easy", "question": "If two angles of a triangle are 30° and 60°, the triangle is:", "options": {"A": "Acute", "B": "Right", "C": "Obtuse", "D": "Equilateral"}, "correct_answer": "B"},
    {"id": 9, "difficulty": "easy", "question": "The sum of angles in any triangle is always:", "options": {"A": "Constant", "B": "Variable", "C": "Depends on sides", "D": "360°"}, "correct_answer": "A"},
    {"id": 10, "difficulty": "easy", "question": "If ∠A = 50°, ∠B = 60°, then ∠C = ?", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "C"},
    {"id": 11, "difficulty": "easy", "question": "An obtuse triangle has one angle:", "options": {"A": "Less than 90°", "B": "Equal to 90°", "C": "Greater than 90°", "D": "Equal to 180°"}, "correct_answer": "C"},
    {"id": 12, "difficulty": "easy", "question": "In an isosceles triangle, if one angle is 40°, what could be another angle?", "options": {"A": "40°", "B": "50°", "C": "90°", "D": "100°"}, "correct_answer": "A"},
    {"id": 13, "difficulty": "easy", "question": "If triangle has angles 2x, 3x, 4x, what is x?", "options": {"A": "10", "B": "20", "C": "30", "D": "40"}, "correct_answer": "B"},
    {"id": 14, "difficulty": "easy", "question": "A triangle cannot have:", "options": {"A": "Two acute angles", "B": "Two obtuse angles", "C": "One right angle", "D": "Three acute angles"}, "correct_answer": "B"},
    {"id": 15, "difficulty": "easy", "question": "If one angle is 110°, sum of other two is:", "options": {"A": "70°", "B": "80°", "C": "90°", "D": "100°"}, "correct_answer": "A"},
    {"id": 16, "difficulty": "easy", "question": "In right triangle, if one acute angle is 35°, other is:", "options": {"A": "45°", "B": "55°", "C": "65°", "D": "75°"}, "correct_answer": "B"},
    {"id": 17, "difficulty": "easy", "question": "If triangle angles are in ratio 1:2:3, largest angle is:", "options": {"A": "30°", "B": "60°", "C": "90°", "D": "120°"}, "correct_answer": "C"},
    {"id": 18, "difficulty": "easy", "question": "Sum of angles of triangle equals sum of angles of:", "options": {"A": "Square", "B": "Straight line", "C": "Right angle", "D": "Circle"}, "correct_answer": "B"},
    {"id": 19, "difficulty": "easy", "question": "If triangle has angles 55°, 55°, 70°, it is:", "options": {"A": "Equilateral", "B": "Isosceles", "C": "Scalene", "D": "Right"}, "correct_answer": "B"},
    {"id": 20, "difficulty": "easy", "question": "Exterior angle of triangle equals sum of:", "options": {"A": "All interior angles", "B": "Two interior opposite angles", "C": "Adjacent interior angle", "D": "Three exterior angles"}, "correct_answer": "B"},
    
    {"id": 21, "difficulty": "medium", "question": "In triangle ABC, ∠A = 60°, ∠B = 70°. Find ∠C.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 22, "difficulty": "medium", "question": "If angles of triangle are (x + 10)°, (2x - 20)°, and (3x + 30)°, find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "B"},
    {"id": 23, "difficulty": "medium", "question": "In right triangle, one acute angle is twice the other. Find both angles.", "options": {"A": "30°, 60°", "B": "40°, 50°", "C": "35°, 55°", "D": "45°, 45°"}, "correct_answer": "A"},
    {"id": 24, "difficulty": "medium", "question": "If one angle of triangle is 100° and other two are equal, find each equal angle.", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    {"id": 25, "difficulty": "medium", "question": "In triangle PQR, ∠P = 55°, ∠Q = 65°. Find ∠R.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 26, "difficulty": "medium", "question": "Angles of triangle are in ratio 2:3:4. Find largest angle.", "options": {"A": "60°", "B": "80°", "C": "100°", "D": "120°"}, "correct_answer": "B"},
    {"id": 27, "difficulty": "medium", "question": "If triangle has angles (3x - 10)°, (x + 20)°, and (2x + 30)°, find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "A"},
    {"id": 28, "difficulty": "medium", "question": "In isosceles triangle, vertex angle is 40°. Find base angles.", "options": {"A": "60°, 60°", "B": "70°, 70°", "C": "80°, 80°", "D": "90°, 90°"}, "correct_answer": "B"},
    {"id": 29, "difficulty": "medium", "question": "If two angles of triangle are 55° and 65°, find third angle.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 30, "difficulty": "medium", "question": "Angles of triangle are (x + 15)°, (2x - 5)°, (3x + 10)°. Find smallest angle.", "options": {"A": "35°", "B": "45°", "C": "55°", "D": "65°"}, "correct_answer": "B"},
    {"id": 31, "difficulty": "medium", "question": "In right triangle, acute angles differ by 20°. Find both.", "options": {"A": "35°, 55°", "B": "40°, 60°", "C": "45°, 65°", "D": "50°, 70°"}, "correct_answer": "A"},
    {"id": 32, "difficulty": "medium", "question": "If triangle angles are (4x)°, (5x)°, (6x)°, find x.", "options": {"A": "10", "B": "12", "C": "15", "D": "20"}, "correct_answer": "B"},
    {"id": 33, "difficulty": "medium", "question": "In triangle, one angle is 70°, second is 50°. Find third.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 34, "difficulty": "medium", "question": "Angles are in ratio 3:5:7. Find middle angle.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 35, "difficulty": "medium", "question": "If triangle has angles (x + 30)°, (2x - 15)°, (3x - 45)°, find x.", "options": {"A": "30", "B": "35", "C": "40", "D": "45"}, "correct_answer": "B"},
    {"id": 36, "difficulty": "medium", "question": "In isosceles triangle, each base angle is 55°. Find vertex angle.", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "B"},
    {"id": 37, "difficulty": "medium", "question": "If two angles are 45° and 75°, find third.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 38, "difficulty": "medium", "question": "Angles are (2x + 10)°, (3x - 20)°, (4x + 10)°. Find largest angle.", "options": {"A": "70°", "B": "80°", "C": "90°", "D": "100°"}, "correct_answer": "C"},
    {"id": 39, "difficulty": "medium", "question": "In right triangle, one acute angle is 15° more than other. Find both.", "options": {"A": "37.5°, 52.5°", "B": "40°, 50°", "C": "35°, 55°", "D": "30°, 60°"}, "correct_answer": "A"},
    {"id": 40, "difficulty": "medium", "question": "If angles are in ratio 1:1:2, find angles.", "options": {"A": "40°, 40°, 100°", "B": "45°, 45°, 90°", "C": "50°, 50°, 80°", "D": "60°, 60°, 60°"}, "correct_answer": "B"},
    {"id": 41, "difficulty": "medium", "question": "In triangle, ∠A = 80°, ∠B = 60°. Find ∠C.", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    {"id": 42, "difficulty": "medium", "question": "Angles are (x + 20)°, (2x - 30)°, (3x - 10)°. Find x.", "options": {"A": "30", "B": "35", "C": "40", "D": "45"}, "correct_answer": "B"},
    {"id": 43, "difficulty": "medium", "question": "In right triangle, acute angles are in ratio 2:3. Find them.", "options": {"A": "36°, 54°", "B": "40°, 50°", "C": "45°, 45°", "D": "30°, 60°"}, "correct_answer": "A"},
    {"id": 44, "difficulty": "medium", "question": "If triangle has angle 120°, other two are equal. Find them.", "options": {"A": "20°, 20°", "B": "30°, 30°", "C": "40°, 40°", "D": "50°, 50°"}, "correct_answer": "B"},
    {"id": 45, "difficulty": "medium", "question": "In triangle XYZ, ∠X = 50°, ∠Y = 70°. Find ∠Z.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 46, "difficulty": "medium", "question": "Angles are in ratio 4:5:6. Find smallest angle.", "options": {"A": "48°", "B": "60°", "C": "72°", "D": "84°"}, "correct_answer": "A"},
    {"id": 47, "difficulty": "medium", "question": "If angles are (3x + 15)°, (4x - 25)°, (2x + 40)°, find x.", "options": {"A": "15", "B": "20", "C": "25", "D": "30"}, "correct_answer": "B"},
    {"id": 48, "difficulty": "medium", "question": "In isosceles triangle, vertex angle is 100°. Find base angles.", "options": {"A": "30°, 30°", "B": "40°, 40°", "C": "50°, 50°", "D": "60°, 60°"}, "correct_answer": "B"},
    {"id": 49, "difficulty": "medium", "question": "If two angles are 35° and 85°, find third.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 50, "difficulty": "medium", "question": "Angles are (x + 10)°, (3x - 20)°, (2x + 30)°. Find middle angle.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "C"},
    {"id": 51, "difficulty": "medium", "question": "In right triangle, one acute angle is 2/3 of other. Find both.", "options": {"A": "36°, 54°", "B": "40°, 50°", "C": "45°, 45°", "D": "30°, 60°"}, "correct_answer": "A"},
    {"id": 52, "difficulty": "medium", "question": "If angles are in ratio 5:6:7, find largest.", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "B"},
    {"id": 53, "difficulty": "medium", "question": "In triangle, ∠A = 75°, ∠B = 55°. Find ∠C.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 54, "difficulty": "medium", "question": "Angles are (2x + 5)°, (3x - 15)°, (4x + 10)°. Find x.", "options": {"A": "20", "B": "25", "C": "30", "D": "35"}, "correct_answer": "A"},
    {"id": 55, "difficulty": "medium", "question": "In right triangle, acute angles differ by 30°. Find them.", "options": {"A": "30°, 60°", "B": "35°, 65°", "C": "40°, 70°", "D": "45°, 75°"}, "correct_answer": "A"},
    {"id": 56, "difficulty": "medium", "question": "If triangle has angle 130°, other two equal. Find them.", "options": {"A": "20°, 20°", "B": "25°, 25°", "C": "30°, 30°", "D": "35°, 35°"}, "correct_answer": "B"},
    {"id": 57, "difficulty": "medium", "question": "In triangle PQR, ∠P = 65°, ∠Q = 45°. Find ∠R.", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "B"},
    {"id": 58, "difficulty": "medium", "question": "Angles in ratio 7:8:9. Find smallest.", "options": {"A": "52.5°", "B": "60°", "C": "67.5°", "D": "75°"}, "correct_answer": "A"},
    {"id": 59, "difficulty": "medium", "question": "If angles are (4x - 10)°, (5x + 20)°, (6x - 30)°, find x.", "options": {"A": "12", "B": "14", "C": "16", "D": "18"}, "correct_answer": "A"},
    {"id": 60, "difficulty": "medium", "question": "In isosceles triangle, base angles each 65°. Find vertex.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 61, "difficulty": "medium", "question": "If two angles 40° and 80°, find third.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 62, "difficulty": "medium", "question": "Angles are (x + 25)°, (2x - 15)°, (3x - 10)°. Find largest.", "options": {"A": "65°", "B": "75°", "C": "85°", "D": "95°"}, "correct_answer": "C"},
    {"id": 63, "difficulty": "medium", "question": "In right triangle, acute angles in ratio 3:4. Find them.", "options": {"A": "30°, 60°", "B": "36°, 54°", "C": "40°, 50°", "D": "45°, 45°"}, "correct_answer": "B"},
    {"id": 64, "difficulty": "medium", "question": "If triangle has angle 140°, other two equal. Find them.", "options": {"A": "15°, 15°", "B": "20°, 20°", "C": "25°, 25°", "D": "30°, 30°"}, "correct_answer": "B"},
    {"id": 65, "difficulty": "medium", "question": "In triangle, ∠A = 85°, ∠B = 35°. Find ∠C.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 66, "difficulty": "medium", "question": "Angles ratio 8:9:10. Find middle.", "options": {"A": "60°", "B": "70°", "C": "80°", "D": "90°"}, "correct_answer": "A"},
    {"id": 67, "difficulty": "medium", "question": "If angles (5x + 5)°, (6x - 10)°, (7x + 5)°, find x.", "options": {"A": "10", "B": "12", "C": "15", "D": "20"}, "correct_answer": "A"},
    {"id": 68, "difficulty": "medium", "question": "In isosceles triangle, vertex 80°. Find base angles.", "options": {"A": "40°, 40°", "B": "50°, 50°", "C": "60°, 60°", "D": "70°, 70°"}, "correct_answer": "B"},
    {"id": 69, "difficulty": "medium", "question": "If two angles 25° and 95°, find third.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 70, "difficulty": "medium", "question": "Angles (3x + 20)°, (4x - 30)°, (5x + 10)°. Find smallest.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 71, "difficulty": "medium", "question": "In right triangle, acute angles differ by 40°. Find them.", "options": {"A": "25°, 65°", "B": "30°, 70°", "C": "35°, 75°", "D": "40°, 80°"}, "correct_answer": "A"},
    {"id": 72, "difficulty": "medium", "question": "If angles ratio 9:10:11, find largest.", "options": {"A": "60°", "B": "66°", "C": "72°", "D": "78°"}, "correct_answer": "B"},
    {"id": 73, "difficulty": "medium", "question": "In triangle, ∠A = 95°, ∠B = 25°. Find ∠C.", "options": {"A": "50°", "B": "60°", "C": "70°", "D": "80°"}, "correct_answer": "B"},
    {"id": 74, "difficulty": "medium", "question": "Angles (x + 30)°, (2x - 20)°, (3x - 10)°. Find x.", "options": {"A": "25", "B": "30", "C": "35", "D": "40"}, "correct_answer": "B"},
    {"id": 75, "difficulty": "medium", "question": "In right triangle, one acute is 3/5 of other. Find both.", "options": {"A": "33.75°, 56.25°", "B": "36°, 54°", "C": "40°, 50°", "D": "45°, 45°"}, "correct_answer": "A"},
    {"id": 76, "difficulty": "medium", "question": "If triangle has angle 150°, other two equal. Find them.", "options": {"A": "10°, 10°", "B": "15°, 15°", "C": "20°, 20°", "D": "25°, 25°"}, "correct_answer": "B"},
    {"id": 77, "difficulty": "medium", "question": "In triangle, ∠A = 105°, ∠B = 25°. Find ∠C.", "options": {"A": "40°", "B": "50°", "C": "60°", "D": "70°"}, "correct_answer": "B"},
    {"id": 78, "difficulty": "medium", "question": "Angles ratio 11:12:13. Find smallest.", "options": {"A": "55°", "B": "60°", "C": "65°", "D": "70°"}, "correct_answer": "A"},
    {"id": 79, "difficulty": "medium", "question": "If angles (6x - 15)°, (7x + 5)°, (8x - 20)°, find x.", "options": {"A": "10", "B": "12", "C": "15", "D": "20"}, "correct_answer": "A"},
    {"id": 80, "difficulty": "medium", "question": "In isosceles triangle, base angles each 70°. Find vertex.", "options": {"A": "30°", "B": "40°", "C": "50°", "D": "60°"}, "correct_answer": "B"},
    
    {"id": 81, "difficulty": "hard", "question": "In triangle ABC, ∠A = (2x + 10)°, ∠B = (3x - 20)°, ∠C = (4x - 30)°. Find all angles.", "options": {"A": "50°, 60°, 70°", "B": "60°, 70°, 50°", "C": "70°, 50°, 60°", "D": "50°, 70°, 60°"}, "correct_answer": "A"},
    {"id": 82, "difficulty": "hard", "question": "If angles of triangle are (x² - 5x)°, (x² + 5)°, and (2x² - 10)°, find x.", "options": {"A": "5", "B": "6", "C": "7", "D": "8"}, "correct_answer": "C"},
    {"id": 83, "difficulty": "hard", "question": "In triangle PQR, ∠P = 1/2∠Q = 1/3∠R. Find all angles.", "options": {"A": "30°, 60°, 90°", "B": "20°, 40°, 120°", "C": "25°, 50°, 105°", "D": "15°, 30°, 135°"}, "correct_answer": "A"},
    {"id": 84, "difficulty": "hard", "question": "If exterior angles at vertices A and B of triangle ABC are 120° and 110° respectively, find all interior angles.", "options": {"A": "60°, 70°, 50°", "B": "50°, 60°, 70°", "C": "70°, 50°, 60°", "D": "60°, 50°, 70°"}, "correct_answer": "A"},
    {"id": 85, "difficulty": "hard", "question": "Angles of triangle are (log₂8x)°, (log₄16x)°, and (log₈64x)°. Find x if angles are in degrees.", "options": {"A": "4", "B": "8", "C": "16", "D": "32"}, "correct_answer": "B"},
    {"id": 86, "difficulty": "hard", "question": "In right triangle, acute angles are such that sinA = cosB. Find all possible angle measures.", "options": {"A": "30°, 60°, 90° or 45°, 45°, 90°", "B": "45°, 45°, 90° only", "C": "30°, 60°, 90° only", "D": "20°, 70°, 90°"}, "correct_answer": "B"},
    {"id": 87, "difficulty": "hard", "question": "If angles satisfy equation: ∠A + ∠B = 2∠C and ∠A - ∠B = 30°, find all angles.", "options": {"A": "65°, 35°, 80°", "B": "70°, 40°, 70°", "C": "75°, 45°, 60°", "D": "80°, 50°, 50°"}, "correct_answer": "C"},
    {"id": 88, "difficulty": "hard", "question": "In triangle, one angle is 60°. The other two angles are such that their difference is 20°. Find all angles.", "options": {"A": "60°, 50°, 70°", "B": "60°, 60°, 60°", "C": "60°, 40°, 80°", "D": "60°, 55°, 65°"}, "correct_answer": "A"},
    {"id": 89, "difficulty": "hard", "question": "If angles are in arithmetic progression with common difference 15°, find angles.", "options": {"A": "45°, 60°, 75°", "B": "50°, 65°, 80°", "C": "55°, 70°, 85°", "D": "40°, 55°, 70°"}, "correct_answer": "A"},
    {"id": 90, "difficulty": "hard", "question": "In triangle ABC, ∠A = ∠B + ∠C. What type of triangle is it?", "options": {"A": "Right triangle", "B": "Acute triangle", "C": "Obtuse triangle", "D": "Equilateral triangle"}, "correct_answer": "A"},
    {"id": 91, "difficulty": "hard", "question": "If angles are (2ⁿ)°, (2ⁿ⁺¹)°, and (2ⁿ⁺²)° where n is integer, find n and angles.", "options": {"A": "n=5, angles: 32°, 64°, 84°", "B": "n=6, angles: 64°, 128°, -12°", "C": "n=5, angles: 32°, 64°, 84°", "D": "No solution"}, "correct_answer": "D"},
    {"id": 92, "difficulty": "hard", "question": "In triangle, angles are such that largest is twice smallest and middle is 20° more than smallest. Find angles.", "options": {"A": "40°, 60°, 80°", "B": "30°, 50°, 100°", "C": "25°, 45°, 110°", "D": "20°, 40°, 120°"}, "correct_answer": "A"},
    {"id": 93, "difficulty": "hard", "question": "If angles satisfy: tanA = 1, sinB = 1/2, and triangle is not right at C, find angles.", "options": {"A": "45°, 30°, 105°", "B": "45°, 45°, 90°", "C": "45°, 60°, 75°", "D": "30°, 60°, 90°"}, "correct_answer": "A"},
    {"id": 94, "difficulty": "hard", "question": "Angles are in geometric progression with ratio 2. Find angles if possible.", "options": {"A": "20°, 40°, 120°", "B": "30°, 60°, 90°", "C": "25°, 50°, 105°", "D": "No such triangle exists"}, "correct_answer": "D"},
    {"id": 95, "difficulty": "hard", "question": "In triangle, sum of two angles equals third angle plus 30°. If smallest angle is 40°, find all angles.", "options": {"A": "40°, 55°, 85°", "B": "40°, 60°, 80°", "C": "40°, 65°, 75°", "D": "40°, 70°, 70°"}, "correct_answer": "C"},
    {"id": 96, "difficulty": "hard", "question": "If angles are (x + y)°, (2x - y)°, and (x + 2y)° and sum is 180°, with x - y = 10, find angles.", "options": {"A": "50°, 60°, 70°", "B": "55°, 65°, 60°", "C": "60°, 50°, 70°", "D": "65°, 55°, 60°"}, "correct_answer": "B"},
    {"id": 97, "difficulty": "hard", "question": "In triangle, one angle is 70°. The other two are in ratio 4:5. Find angles.", "options": {"A": "70°, 48°, 62°", "B": "70°, 50°, 60°", "C": "70°, 44°, 66°", "D": "70°, 40°, 70°"}, "correct_answer": "C"},
    {"id": 98, "difficulty": "hard", "question": "If angles of triangle form arithmetic progression and largest angle is 80°, find all angles.", "options": {"A": "40°, 60°, 80°", "B": "50°, 65°, 80°", "C": "55°, 70°, 80°", "D": "60°, 70°, 80°"}, "correct_answer": "A"},
    {"id": 99, "difficulty": "hard", "question": "Angles are such that ∠A = 2∠B = 3∠C. Find angles in degrees.", "options": {"A": "90°, 45°, 45°", "B": "120°, 60°, 0°", "C": "108°, 54°, 18°", "D": "100°, 50°, 30°"}, "correct_answer": "C"},
    {"id": 100, "difficulty": "hard", "question": "In triangle, if ∠A + ∠B = 130° and ∠B + ∠C = 110°, find all angles.", "options": {"A": "70°, 60°, 50°", "B": "80°, 50°, 50°", "C": "90°, 40°, 50°", "D": "100°, 30°, 50°"}, "correct_answer": "A"}
  ]
}