Question

The $\angle B$ in the given triangle is ___ degree.

Answer 1

In the given triangle, $A{B}^2=8^2=64A{C}^2={15}^2=225B{C}^2={17}^2=289$
We can see that $B{C}^2=A{C}^2+A{B}^2$, which implies ABC is a right angled triangle with $\angle A={90}^{\circ }$
Now $\angle A+\angle B+\angle C={180}^{\circ }$ (sum of angle) $\Rightarrow \angle B=180-(90+30)\angle B={60}^{\circ }$