Question

Find B
............​

Answer 1

Given:

In ΔABC, AB = 5 unit, BC = 2 unit and ∠C = 90°

To find the The value of ∠B.

Formula

By Trigonometric Ratio we know,

`cos \ \theta=(adj)/(hyp)`

Let us take ∠B = θ

With respect to θ, BC is the adjacent side and AB is the hypotenuse.

So,

`cos \ \theta=(BC)/(AB)`

`cos \ B=(2)/(5)`

`B=cos^(-1) ((2)/(5) )`

`B = 66.42^(\circ)`

Hence, the value of ∠B is 66.42°.