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| Maths Quiz for Class 7 Properties of Triangles |
In this post, you will find 20 online maths quiz questions for
class 7 properties of triangles. Online maths quiz will take around 20 minutes
to complete it.
Question 1: The altitude AD of ΔABC makes a/an ____________ angle with the side BC.
A) acute
B) obtuse
C) right
D) straight
Explanation: The altitude AD of ΔABC makes a right angle with the side BC.
Question 2: If AD is a median of ΔABC from the vertex A to side BC, then which of the following is correct?
A) BD = CD
B) BD > CD
C) BD < CD
D) None of these
Explanation: BD = CD, because the median divides the opposite side in two equal parts.
Question 3: Two angles of a triangle are 50° and 65°. What is the measure of the third angle?
A) x = 65°
B) x = 60°
C) x = 55°
D) x = 45°
Explanation: Let the measure of the third angle be x°. Sum of the angles of a triangle = 180° => 50° + 65° + x = 180° => 115° + x = 180° => x = 180° – 115° => x = 65°
Question 4: The angles of a triangle are in the ratio 3 : 2 : 5. Find the measure of the smallest angle of the triangle.
A) x = 54°
B) x = 36°
C) x = 72°
D) x = 90°
Explanation: Let the three angles be 3x, 2x and 5x. Sum of the angles of a triangle = 180° => 3x + 2x + 5x = 180° => 10x = 180° => x = 180/10 => x = 18°. Thus, the smallest angle = 2x = 2 × 18° = 36°
Question 5: In the given figure, find the value of x.
A) x = 20°
B) x = 100°
C) x = 110°
D) x = 90°
Explanation: The exterior angle is equal to the sum of the opposite interior angles. Therefore, x = 60° + 40° = 100°
Question 6: Find the value of x from the given figure.
A) x = 65°
B) x = 35°
C) x = 45°
D) x = 55°
Explanation: The exterior angle is equal to the sum of the opposite interior angles. Therefore, 80° + x° = 125° => x° = 125° – 80° => x° = 45°
Question 7: What is the value of x in the given figure?
A) x = 60°
B) x = 50°
C) x = 70°
D) x = 40°
Explanation: The sum of the angles of a triangle is 180° => 60° + 70° + x° = 180° => 130° + x° = 180° => x° = 180° – 130° => x° = 50°
Question 8: In the given figure, the value of x is _____________.
A) x = 50°
B) x = 40°
C) x = 20°
D) x = 10°
Explanation: The sum of the angles of a triangle is 180° => 90° + 5x° + 4x° = 180° => 90° + 9x° = 180° => 9x° = 180° – 90° => 9x° = 90° => x° = 10°
Question 9: If the two angles of a triangle are 72° and 54°, then the third angle is _____________.
A) x = 54°
B) x = 50°
C) x = 60°
D) x = 40°
Explanation: Let the third angle be x°. The sum of the angles of a triangle is 180° => 72° + 54° + x° = 180° => 126° + x° = 180° => x° = 180° – 126° => x° = 54°
Question 10: The angles of a triangle are x, 2x and 3x. Find the value of x.
A) x = 60°
B) x = 50°
C) x = 30°
D) x = 40°
Explanation: The sum of the angles of a triangle is 180°. Then, x + 2x + 3x = 180° => 6x = 180 => x = 180/6 => x = 30°
Question 11: The angles of a triangle are 2x°, 60° and 40°. What is the value of x?
A) x = 50°
B) x = 40°
C) x = 30°
D) x = 20°
Explanation: The sum of the angles of a triangle is 180°. Then, 2x° + 60° + 40° = 180° => 2x° + 100° = 180° => 2x° = 180° – 100° => 2x° = 80° => x° = 80°/2 => x° = 40°
Question 12: Which of the following are angles of a triangle?
A) 90°, 40°, 30°
B) 90°, 40°, 50°
C) 80°, 70°, 50°
D) 70°, 60°, 40°
Explanation: 90°, 40°, 50° are the angles of a triangle because 90° + 40° + 50° = 180°
Question 13: Which of the following are not the angles of a triangle?
A) 75°, 65°, 45°
B) 60°, 40°, 80°
C) 40°, 50°, 90°
D) 50°, 60°, 70°
Explanation: 75°, 65°, 45° are not the angles of a triangle because 75° + 65° + 45° = 185° which is not equal to 180°.
Question 14: Which of the following can be the sides of a triangle?
A) 9.5 cm, 4.5 cm, 4 cm
B) 3 cm, 4 cm, 8 cm
C) 2 cm, 3 cm, 5 cm
D) 5.5 cm, 6 cm, 7.5 cm
Explanation: 5.5 cm, 6 cm, 7.5 cm can be the sides of a triangle because 5.5 + 6 > 7.5.
Question 15: Which of the following cannot be the sides of a triangle?
A) 5.2 cm, 7.1 cm, 4.5 cm
B) 3.8 cm, 4.8 cm, 5.5 cm
C) 4 cm, 8 cm, 3.5 cm
D) 6 cm, 7 cm, 8 cm
Explanation: 4 cm, 8 cm, 3.5 cm cannot be the sides of a triangle because 4 + 3.5 < 8.
Question 16: The measure of each angle of an equilateral triangle is _________________.
A) 90°
B) 60°
C) 180°
D) 360°
Explanation: The angles of an equilateral triangle are equal in measure. Let each angles measure x°. Then, x° + x° + x° = 180° => 3x° = 180° => x = 180/3 = 60°
Question 17: In an isosceles triangle, the measure of the vertex angle is 40°. Find the measure of each of the base angles.
A) 70°
B) 80°
C) 90°
D) 60°
Explanation: Let each base angle be x°. Then, x° + x° + 40° = 180° => 2x° + 40° = 180° => 2x° = 180° – 40° => 2x° = 140° => x = 140/2 = 70°
Question 18: In a right-angled triangle, one acute angle measures 40°. Find the measure of the other acute angle.
A) 25°
B) 40°
C) 50°
D) 60°
Explanation: The other acute angle = 90° – 40° = 50°
Question 19: In a right-angled triangle, the base and height measure 5 cm and 12 cm. Find the length of the hypotenuse.
A) 17 cm
B) 13 cm
C) 14 cm
D) 15 cm
Explanation: (Hypotenuse)2 = (base)2 + (height)2 => (Hypotenuse)2 = (5)2 + (12)2 => (Hypotenuse)2 = 25 + 144 => (Hypotenuse)2 = 169 => Hypotenuse = √169 = 13 cm
Question 20: In a triangle ABC right angled at B, AB = 15 cm, AC = 25 cm. Find the length of BC.
A) 16 cm
B) 18 cm
C) 20 cm
D) 22 cm
Explanation: In triangle ABC, AC is the hypotenuse. Then, BC2 = AC2 – AB2 => BC2 = 252 – 152 => BC2 = 625 – 225 => BC2 = 400 => BC = √400 => BC = 20 cm
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