Question

In the following diagram, and are tangents to the circle. Find the value of: a) $\angle$AOB b) $\angle$OBA given = 7 cm.

Answer 1

a) $\angle$AOB + $\angle$APB = ${180}^0$

$\angle$AOB + ${48}^0$ = ${180}^0$

$\angle$AOB = ${132}^0$

b) $\angle$OBA + $\angle$OAB + $\angle$AOB = ${180}^0$

2 $\times$ $\angle$OBA + $\angle$AOB = ${180}^0$ ( $\angle$OBA = $\angle$OAB)

$\angle$OBA = ${24}^0$