Madhya Pradesh Police Exam Model Paper 9

Question : 75 of 100

Marks: +1, -0

∠A, ∠B and ∠C are three angles of a triangle and ∠A/4 + ∠B/4 + ∠C/5 = 41°, then find the value of ∠A + ∠B = ?

120°
100°
90°
80°

Solution:

Given,
∠A, ∠B and ∠C are three angles of a triangle
.∠A/4 + ∠B/4 + ∠C/5 = 41°
Formula:
Sum of all three angles of a triangle is 180°.
Calculation:

∠A{/}4 + ∠B{/}4 + ∠C{/}5 = 41°

⇒ (5∠A + 5∠B + 4∠C){/}20 = 41°

⇒ (∠A + 4∠A + ∠B + 4∠B + 4∠C){/}20 = 41°

⇒ (∠A + ∠B + 4∠A + 4∠B + 4∠C){/}20 = 41°

⇒ ∠A + ∠B + 4(∠A + ∠B + ∠C) = 41° × 20

⇒ ∠A + ∠B + 4 × 180° = 820°

⇒ ∠A + ∠B = 820° - 720°

⇒ ∠A + ∠B = 100°

∴ The value of ∠A + ∠B is 100°

Go to Question:

Prev Question

Next Question