Quiz for Properties of Triangles

Q1: In triangle ABC, if a² = b² + c², then angle A is:

A. 90° B. 60° C. 120° D. 30°

Q2: If the angles of triangle are in A.P., then the triangle is:

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

Q3: In triangle ABC, if sin A = 1, then angle A is:

A. 30° B. 45° C. 60° D. 90°

Q4: In triangle ABC, area = (1/2)ab sin C is known as:

A. Sine rule B. Cosine rule C. Area formula D. Heron’s formula

Q5: In triangle ABC, if angle B = 90°, then sin A =

A. a/c B. b/c C. c/a D. a/b

Q6: In triangle ABC, if a = b = c, then triangle is:

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

Q7: The value of angle A in triangle ABC if a = √3, b = 1, C = 90° is:

A. 30° B. 45° C. 60° D. 90°

Q8: Law of sines states that:

A. a/sin A = b/sin B = c/sin C B. a² = b² + c² – 2bc cos A C. sin A + sin B + sin C = 1 D. Area = (1/2)ab sin C

Q9: A triangle is possible if sum of any two sides is:

A. > third side B. = third side C. < third side D. Equal to 180°

Q10: The largest angle in triangle lies opposite to:

A. Longest side B. Shortest side C. Middle side D. Equal side

Q11: Cos A in triangle with sides a, b, c is given by:

A. (b² + c² – a²)/2bc B. (a² + b² – c²)/2ab C. (a² + c² – b²)/2ac D. (a² – b² + c²)/2bc

Q12: The radius r of incircle in triangle is:

A. Area / semi-perimeter B. Area / perimeter C. Area × perimeter D. semi-perimeter / Area

Q13: In triangle ABC, sin A = a/2R is:

A. Sine rule B. Cosine rule C. Area rule D. Heron’s formula

Q14: Triangle with all angles < 90° is:

A. Acute B. Obtuse C. Right D. Equilateral

Q15: Triangle with one angle = 90° is called:

A. Right triangle B. Acute triangle C. Obtuse triangle D. Equilateral triangle

Q16: If a = 5, b = 12, c = 13, triangle is:

A. Right triangle B. Acute triangle C. Obtuse triangle D. Equilateral triangle

Q17: In triangle ABC, sin A/sin B =

A. a/b B. b/a C. c/b D. b/c

Q18: In triangle ABC, median divides triangle into:

A. Two equal areas B. Three equal parts C. Right triangle D. Congruent triangles

Q19: In triangle, angle sum is:

A. 180° B. 90° C. 360° D. 270°

Q20: If angle A = 120°, triangle is:

A. Obtuse B. Acute C. Right D. Equilateral