{
  "title": "Triangles Properties & Construction - Grade 5 ICSE",
  "total_questions": 60,
  "questions": [
    {
      "id": 1,
      "difficulty": "easy",
      "question": "How many sides does a triangle have? 🔺",
      "options": { "A": "2", "B": "3", "C": "4", "D": "5" },
      "correct_answer": "B"
    },
    {
      "id": 2,
      "difficulty": "easy",
      "question": "The sum of angles in a triangle is ____. 📐",
      "options": { "A": "90°", "B": "180°", "C": "270°", "D": "360°" },
      "correct_answer": "B"
    },
    {
      "id": 3,
      "difficulty": "easy",
      "question": "A triangle with all sides equal is ____. 🔺",
      "options": {
        "A": "Isosceles",
        "B": "Scalene",
        "C": "Equilateral",
        "D": "Right"
      },
      "correct_answer": "C"
    },
    {
      "id": 4,
      "difficulty": "easy",
      "question": "A triangle with one 90° angle is ____. ⭐",
      "options": {
        "A": "Acute",
        "B": "Obtuse",
        "C": "Right",
        "D": "Equilateral"
      },
      "correct_answer": "C"
    },
    {
      "id": 5,
      "difficulty": "easy",
      "question": "All angles in an equilateral triangle are ____. 🔺",
      "options": { "A": "45°", "B": "60°", "C": "90°", "D": "120°" },
      "correct_answer": "B"
    },
    {
      "id": 6,
      "difficulty": "easy",
      "question": "A triangle with no equal sides is ____. 📐",
      "options": {
        "A": "Equilateral",
        "B": "Isosceles",
        "C": "Scalene",
        "D": "Right"
      },
      "correct_answer": "C"
    },
    {
      "id": 7,
      "difficulty": "easy",
      "question": "In a right triangle, the side opposite the right angle is the ____. 📏",
      "options": { "A": "Base", "B": "Height", "C": "Hypotenuse", "D": "Leg" },
      "correct_answer": "C"
    },
    {
      "id": 8,
      "difficulty": "easy",
      "question": "A triangle with all angles less than 90° is ____. 🔺",
      "options": {
        "A": "Acute",
        "B": "Obtuse",
        "C": "Right",
        "D": "Equilateral"
      },
      "correct_answer": "A"
    },
    {
      "id": 9,
      "difficulty": "easy",
      "question": "How many altitudes does a triangle have? 📐",
      "options": { "A": "1", "B": "2", "C": "3", "D": "4" },
      "correct_answer": "C"
    },
    {
      "id": 10,
      "difficulty": "easy",
      "question": "The point where all medians meet is called ____. ⭐",
      "options": {
        "A": "Centroid",
        "B": "Circumcenter",
        "C": "Incenter",
        "D": "Orthocenter"
      },
      "correct_answer": "A"
    },
    {
      "id": 11,
      "difficulty": "easy",
      "question": "Area of triangle = ½ × ____ × height. 📏",
      "options": {
        "A": "Base",
        "B": "Side",
        "C": "Perimeter",
        "D": "Diagonal"
      },
      "correct_answer": "A"
    },
    {
      "id": 12,
      "difficulty": "easy",
      "question": "A triangle with two equal sides is ____. 🔺",
      "options": {
        "A": "Scalene",
        "B": "Isosceles",
        "C": "Equilateral",
        "D": "Right"
      },
      "correct_answer": "B"
    },
    {
      "id": 13,
      "difficulty": "easy",
      "question": "In ΔABC, if ∠A=60°, ∠B=60°, then ∠C=____. 📐",
      "options": { "A": "30°", "B": "60°", "C": "90°", "D": "120°" },
      "correct_answer": "B"
    },
    {
      "id": 14,
      "difficulty": "easy",
      "question": "The longest side of a right triangle is the ____. 📏",
      "options": { "A": "Base", "B": "Height", "C": "Hypotenuse", "D": "Leg" },
      "correct_answer": "C"
    },
    {
      "id": 15,
      "difficulty": "easy",
      "question": "All equilateral triangles are also ____. 🔄",
      "options": {
        "A": "Right",
        "B": "Obtuse",
        "C": "Isosceles",
        "D": "Scalene"
      },
      "correct_answer": "C"
    },
    {
      "id": 16,
      "difficulty": "easy",
      "question": "In an isosceles triangle, angles opposite equal sides are ____. ⚖️",
      "options": {
        "A": "Equal",
        "B": "Different",
        "C": "Right",
        "D": "Complementary"
      },
      "correct_answer": "A"
    },
    {
      "id": 17,
      "difficulty": "easy",
      "question": "Perimeter of triangle = sum of all ____. 📏",
      "options": {
        "A": "Angles",
        "B": "Sides",
        "C": "Heights",
        "D": "Medians"
      },
      "correct_answer": "B"
    },
    {
      "id": 18,
      "difficulty": "easy",
      "question": "A triangle cannot have more than one ____ angle. ❌",
      "options": { "A": "Acute", "B": "Right", "C": "Obtuse", "D": "Equal" },
      "correct_answer": "C"
    },
    {
      "id": 19,
      "difficulty": "easy",
      "question": "In ΔPQR, if PQ=QR, it is ____ triangle. 🔺",
      "options": {
        "A": "Scalene",
        "B": "Isosceles",
        "C": "Equilateral",
        "D": "Right"
      },
      "correct_answer": "B"
    },
    {
      "id": 20,
      "difficulty": "easy",
      "question": "Smallest possible number of acute angles in a triangle is ____. 📐",
      "options": { "A": "0", "B": "1", "C": "2", "D": "3" },
      "correct_answer": "C"
    },
    {
      "id": 21,
      "difficulty": "medium",
      "question": "In ΔABC, ∠A=50°, ∠B=70°, ∠C=____. 📐",
      "options": { "A": "50°", "B": "60°", "C": "70°", "D": "80°" },
      "correct_answer": "B"
    },
    {
      "id": 22,
      "difficulty": "medium",
      "question": "If two angles of triangle are 45° and 55°, it is ____ triangle. 🔺",
      "options": {
        "A": "Acute",
        "B": "Right",
        "C": "Obtuse",
        "D": "Equilateral"
      },
      "correct_answer": "A"
    },
    {
      "id": 23,
      "difficulty": "medium",
      "question": "In right Δ, if one acute angle is 30°, the other is ____. 📐",
      "options": { "A": "30°", "B": "45°", "C": "60°", "D": "90°" },
      "correct_answer": "C"
    },
    {
      "id": 24,
      "difficulty": "medium",
      "question": "Area of triangle with base 10cm, height 6cm = ____ cm². 📏",
      "options": { "A": "30", "B": "40", "C": "50", "D": "60" },
      "correct_answer": "A"
    },
    {
      "id": 25,
      "difficulty": "medium",
      "question": "In isosceles Δ, vertex angle=40°. Each base angle=____. 🔺",
      "options": { "A": "40°", "B": "60°", "C": "70°", "D": "80°" },
      "correct_answer": "C"
    },
    {
      "id": 26,
      "difficulty": "medium",
      "question": "Can we construct triangle with sides 3cm, 4cm, 8cm? 🛠️",
      "options": {
        "A": "Yes",
        "B": "No",
        "C": "Sometimes",
        "D": "Only if right"
      },
      "correct_answer": "B"
    },
    {
      "id": 27,
      "difficulty": "medium",
      "question": "In ΔXYZ, if XY=6cm, YZ=8cm, XZ=10cm, it is ____ Δ. 📐",
      "options": {
        "A": "Acute",
        "B": "Right",
        "C": "Obtuse",
        "D": "Equilateral"
      },
      "correct_answer": "B"
    },
    {
      "id": 28,
      "difficulty": "medium",
      "question": "Sum of any two sides of triangle is ____ third side. ➕",
      "options": {
        "A": "Equal to",
        "B": "Less than",
        "C": "Greater than",
        "D": "Half of"
      },
      "correct_answer": "C"
    },
    {
      "id": 29,
      "difficulty": "medium",
      "question": "In equilateral Δ, each exterior angle = ____. 🔺",
      "options": { "A": "60°", "B": "90°", "C": "120°", "D": "180°" },
      "correct_answer": "C"
    },
    {
      "id": 30,
      "difficulty": "medium",
      "question": "If triangle sides are 7cm, 24cm, 25cm, area = ____ cm². 📏",
      "options": { "A": "84", "B": "96", "C": "108", "D": "120" },
      "correct_answer": "A"
    },
    {
      "id": 31,
      "difficulty": "medium",
      "question": "Altitude of equilateral Δ with side 10cm ≈ ____ cm. 📐",
      "options": {
        "A": "7.5",
        "B": "8.66",
        "C": "9",
        "D": "10"
      },
      "correct_answer": "B"
    },
    {
      "id": 32,
      "difficulty": "medium",
      "question": "In ΔABC, if ∠A=2∠B=3∠C, then ∠A=____. 🔍",
      "options": {
        "A": "60°",
        "B": "72°",
        "C": "90°",
        "D": "98°"
      },
      "correct_answer": "D"
    },
    {
      "id": 33,
      "difficulty": "medium",
      "question": "Median divides triangle into two ____ areas. ⚖️",
      "options": { "A": "Equal", "B": "Different", "C": "Half", "D": "Double" },
      "correct_answer": "A"
    },
    {
      "id": 34,
      "difficulty": "medium",
      "question": "Construct triangle with sides 5cm, 6cm, 7cm. Largest angle opposite side ____ cm. 🛠️",
      "options": { "A": "5", "B": "6", "C": "7", "D": "Equal" },
      "correct_answer": "C"
    },
    {
      "id": 35,
      "difficulty": "medium",
      "question": "If triangle angles are in ratio 1:2:3, it is ____ triangle. 📊",
      "options": {
        "A": "Acute",
        "B": "Right",
        "C": "Obtuse",
        "D": "Equilateral"
      },
      "correct_answer": "B"
    },
    {
      "id": 36,
      "difficulty": "medium",
      "question": "In right Δ, legs are 9cm, 12cm. Hypotenuse = ____ cm. 📏",
      "options": { "A": "13", "B": "15", "C": "17", "D": "21" },
      "correct_answer": "B"
    },
    {
      "id": 37,
      "difficulty": "medium",
      "question": "Altitude of triangle is ____ to base. 📐",
      "options": {
        "A": "Parallel",
        "B": "Perpendicular",
        "C": "Equal",
        "D": "Half"
      },
      "correct_answer": "B"
    },
    {
      "id": 38,
      "difficulty": "medium",
      "question": "Can Δ have angles 70°, 80°, 30°? 🤔",
      "options": {
        "A": "Yes",
        "B": "No",
        "C": "Only if right",
        "D": "Only if acute"
      },
      "correct_answer": "A"
    },
    {
      "id": 39,
      "difficulty": "medium",
      "question": "In Δ, if one angle=120°, sum of other two=____. ➕",
      "options": { "A": "60°", "B": "90°", "C": "120°", "D": "180°" },
      "correct_answer": "A"
    },
    {
      "id": 40,
      "difficulty": "medium",
      "question": "Triangle with sides 5,12,13 is ____ triangle. 📐",
      "options": {
        "A": "Acute",
        "B": "Right",
        "C": "Obtuse",
        "D": "Isosceles"
      },
      "correct_answer": "B"
    },
    {
      "id": 41,
      "difficulty": "hard",
      "question": "In ΔABC, ∠A=58°, ∠B=62°. Longest side is opposite angle ____. 🔍",
      "options": {
        "A": "A",
        "B": "B",
        "C": "C",
        "D": "Equal"
      },
      "correct_answer": "B"
    },
    {
      "id": 42,
      "difficulty": "hard",
      "question": "Construct triangle with angles 55°, 65°, 60°. Possible? 🛠️",
      "options": {
        "A": "Yes",
        "B": "No",
        "C": "Only with ruler",
        "D": "Infinite triangles"
      },
      "correct_answer": "A"
    },
    {
      "id": 43,
      "difficulty": "hard",
      "question": "In right Δ, altitude to hypotenuse divides it into two similar triangles. If segments are 4cm and 9cm, altitude=____ cm. 📏",
      "options": { "A": "6", "B": "8", "C": "10", "D": "12" },
      "correct_answer": "A"
    },
    {
      "id": 44,
      "difficulty": "hard",
      "question": "Area of equilateral Δ with side 'a' = ____. 📐",
      "options": { "A": "a²√3/2", "B": "a²√3/4", "C": "a√3/2", "D": "a√3/4" },
      "correct_answer": "B"
    },
    {
      "id": 45,
      "difficulty": "hard",
      "question": "In Δ, sides are 8,15,17. Area = ____. 📏",
      "options": { "A": "60", "B": "68", "C": "72", "D": "84" },
      "correct_answer": "A"
    },
    {
      "id": 46,
      "difficulty": "hard",
      "question": "In isosceles right Δ, hypotenuse=10√2 cm. Each leg=____ cm. 🔺",
      "options": { "A": "5", "B": "10", "C": "12", "D": "15" },
      "correct_answer": "B"
    },
    {
      "id": 47,
      "difficulty": "hard",
      "question": "Triangle inequality: For sides a,b,c, which is true? 📐",
      "options": { "A": "a+b<c", "B": "a-b>c", "C": "a+b>c", "D": "a+b=c" },
      "correct_answer": "C"
    },
    {
      "id": 48,
      "difficulty": "hard",
      "question": "In ΔABC, ∠B=90°, AB=5, BC=12. AC=____. 📏",
      "options": { "A": "13", "B": "14", "C": "15", "D": "17" },
      "correct_answer": "A"
    },
    {
      "id": 49,
      "difficulty": "hard",
      "question": "Two triangles are congruent if ____ sides and ____ angles are equal. ⚖️",
      "options": {
        "A": "2,1",
        "B": "3,3",
        "C": "2,2",
        "D": "1,1"
      },
      "correct_answer": "B"
    },
    {
      "id": 50,
      "difficulty": "hard",
      "question": "In Δ, medians intersect at centroid dividing each in ratio ____. ⭐",
      "options": { "A": "1:1", "B": "1:2", "C": "2:1", "D": "3:1" },
      "correct_answer": "C"
    },
    {
      "id": 51,
      "difficulty": "hard",
      "question": "Construct triangle given base=7cm, base angles=45°,60°. Possible? 🛠️",
      "options": {
        "A": "Yes",
        "B": "No",
        "C": "Only one",
        "D": "Two triangles"
      },
      "correct_answer": "A"
    },
    {
      "id": 52,
      "difficulty": "hard",
      "question": "In Δ, if sides are 7,24,25, it is ____ triangle. 📐",
      "options": {
        "A": "Acute",
        "B": "Right",
        "C": "Obtuse",
        "D": "Isosceles"
      },
      "correct_answer": "B"
    },
    {
      "id": 53,
      "difficulty": "hard",
      "question": "Altitude of equilateral Δ with perimeter 30cm = ____ cm. 📏",
      "options": { "A": "5√3", "B": "7.5√3", "C": "10√3", "D": "15√3" },
      "correct_answer": "A"
    },
    {
      "id": 54,
      "difficulty": "hard",
      "question": "In ΔABC, ∠A=40°, ∠B=80°. Longest side is ____. 🔍",
      "options": { "A": "AB", "B": "BC", "C": "CA", "D": "Equal" },
      "correct_answer": "B"
    },
    {
      "id": 55,
      "difficulty": "hard",
      "question": "Right Δ area=30cm², one leg=5cm. Other leg=____ cm. 📏",
      "options": { "A": "6", "B": "8", "C": "10", "D": "12" },
      "correct_answer": "D"
    },
    {
      "id": 56,
      "difficulty": "hard",
      "question": "In scalene Δ, all sides different. Can two angles be equal? 🤔",
      "options": {
        "A": "Yes",
        "B": "No",
        "C": "Only if right",
        "D": "Only if obtuse"
      },
      "correct_answer": "B"
    },
    {
      "id": 57,
      "difficulty": "hard",
      "question": "Construct triangle with sides 6,8,10. Largest altitude is to side ____ cm. 🛠️",
      "options": { "A": "6", "B": "8", "C": "10", "D": "All equal" },
      "correct_answer": "A"
    },
    {
      "id": 58,
      "difficulty": "hard",
      "question": "In Δ, exterior angle = sum of ____ interior angles. ➕",
      "options": {
        "A": "All three",
        "B": "Two opposite",
        "C": "Adjacent",
        "D": "None"
      },
      "correct_answer": "B"
    },
    {
      "id": 59,
      "difficulty": "hard",
      "question": "Triangle with sides 13,14,15. Area ≈ ____ (using Heron's). 📏",
      "options": { "A": "78", "B": "84", "C": "91", "D": "98" },
      "correct_answer": "B"
    },
    {
      "id": 60,
      "difficulty": "hard",
      "question": "In right Δ, if one acute angle is twice the other, angles are ____. 📐",
      "options": {
        "A": "30°,60°",
        "B": "40°,50°",
        "C": "45°,45°",
        "D": "20°,70°"
      },
      "correct_answer": "A"
    }
  ]
}