Question

In triangle ABC , m angle A=65 If m angle B-m angle C=25 , find m angle B .​

Answer 1

Given :

In a triangle ABC

• Measure of ∠A is 65°
• Measure of ∠C is 25°

What To Find :

• Measure of ∠B

Concept :

The angles sum property of a triangle :

The sum of the interior angles of a triangle is 180°

• ∠A + ∠B + ∠C = 180°

Solution :

According to the concept

• ∠A + ∠B + ∠C = 180°

So ,

$\begin{cases}\large\bf\blue{ \implies} \rm \:65 \degree \: + \: ∠B \: + \: 25 \degree \: = \: 180 \degree \\ \\ \large\bf\blue{ \implies} \rm \:90 \degree \: + \: ∠B \: = \: 180 \degree \\ \\ \large\bf\blue{ \implies} \rm \:∠B \: = \: 180 \degree \: - \: 90 \degree \\ \\ \large\bf\blue{ \implies} \rm \:∠B \: = \: 90 \degree \end{cases}$

Hence , the measure of ∠B is 90°