Question

1. In triangle ABC, m∠A=36, and m∠C=12. Calculate m∠B.

2. In triangle ABC, m∠A=40, and m∠C=27. Calculate m∠B.

Answer 1

1) m ∠B = 132°

2) m ∠B = 113°

Explanation:

1. In triangle ABC, m ∠A=36, and m ∠C=12. Calculate m ∠B.

We are given measure of 2 angles and we need to find the third angle.

We know that, sum of angles of triangle = 180°

We can write as:

∠A + ∠B + ∠C = 180°

Now put m ∠A=36 and m ∠C=12, to find m ∠B

`\angle A + \angle B + \angle C = 180\\36+ \angle B +12=180\\\angle B+48=180\\\angle B=180-48\\\angle B=132`

So, we get m ∠B = 132°

2. In triangle ABC, m ∠A=40, and m ∠C=27. Calculate m ∠B.

We are given measure of 2 angles and we need to find the third angle.

We know that, sum of angles of triangle = 180°

We can write as:

∠A + ∠B + ∠C = 180°

Now put m ∠A=40 and m ∠C=27, to find m ∠B

`\angle A + \angle B + \angle C = 180\\40+ \angle B +27=180\\\angle B+67=180\\\angle B=180-67\\\angle B=113`

So, we get m ∠B = 113°