Question

Find $\angle AOB$ in the given figure.

Answer 1

$\angle A=\angle B={90}^o$(tangent is perpendicular)

So $\angle AOB+\angle A+\angle B+{30}^o={360}^o$

$\angle AOB+{90}^o+{90}^o+{30}^o={360}^o$

$\angle AOB={360}^o-{210}^o$

$\angle AOB={150}^o$.