A Tale of Three Intersecting Lines — Practice

Q1. A triangle is best described as a closed figure formed by

• A. Two rays starting from a common vertex
• B. A single curve that returns to its starting point
• C. Three line segments joining three corner points
• D. Four line segments meeting at four corner points

Q2. Every triangle has exactly

• A. Two vertices, three sides and three angles
• B. Three vertices, four sides and three angles
• C. Three vertices, three sides and four angles
• D. Three vertices, three sides and three angles

Q3. An equilateral triangle is a triangle in which

• A. Exactly two sides are of equal length
• B. All three sides are of equal length
• C. All three sides are of different lengths
• D. One side equals the sum of the other two

Q4. A triangle in which exactly two sides are of equal length is called

• A. Scalene triangle
• B. Isosceles triangle
• C. Right-angled triangle
• D. Obtuse-angled triangle

Q5. A triangle whose three sides are of three different lengths is called

• A. Isosceles triangle
• B. Equilateral triangle
• C. Right-angled triangle
• D. Scalene triangle

Q6. A set of three lengths is said to satisfy the triangle inequality when

• A. All three lengths are equal
• B. Each length is smaller than the sum of the other two lengths
• C. Each length is greater than the sum of the other two lengths
• D. The longest length equals the sum of the other two

Q7. Which of the following sets of lengths (in cm) can be the sides of a triangle?

• A. 2, 2, 5
• B. 2, 4, 8
• C. 3, 4, 6
• D. 10, 20, 35

Q8. The angle sum property of a triangle states that the sum of its three angles is always

• A. 90°
• B. 120°
• C. 180°
• D. 360°

Q9. In a triangle ABC, ∠B = 50° and ∠C = 70°. What is the measure of ∠A?

• A. 60°
• B. 70°
• C. 100°
• D. 120°

Q10. A right-angled triangle is a triangle in which

• A. All three angles are equal to 90°
• B. Exactly one angle is equal to 90°
• C. All three angles are less than 90°
• D. One angle is greater than 90°

Q11. An acute-angled triangle is a triangle in which

• A. Exactly one angle is acute
• B. Two angles are acute and one is right
• C. All three angles are acute (less than 90°)
• D. One angle is obtuse and two are acute

Q12. An altitude of a triangle is defined as

• A. Any line segment drawn from one vertex to another
• B. A line segment joining the midpoints of two sides
• C. A line through two vertices parallel to the third side
• D. A line segment from a vertex perpendicular to the opposite side

Q13. An exterior angle of a triangle is the angle formed between

• A. The extension of one side of the triangle and the adjacent side
• B. Two sides of the triangle meeting at a vertex
• C. The altitude of a triangle and its base
• D. Two extensions of the same side in opposite directions

Q14. When two sides and an included angle of a triangle are given, the included angle is the angle

• A. Opposite to one of the two given sides
• B. Between the two given sides
• C. Equal to half of the largest given side
• D. Made by extending one of the given sides

Q15. To construct an equilateral triangle of side 4 cm using a compass after drawing the base AB = 4 cm, the next step is to

• A. Draw a straight line through A perpendicular to AB
• B. Construct arcs of radius 4 cm from A and from B and mark their intersection as C
• C. Mark a point C anywhere above AB and join AC and BC
• D. Construct an arc of radius 8 cm from the midpoint of AB