Question

In the figure, if $\angle ABC={20}^{\circ }$, then $\angle AOC$ is equal to

• A. ${10}^{\circ }$
• B. ${20}^{\circ }$
• C. ${40}^{\circ }$
• D. ${60}^{\circ }$

Answer 1

The correct option is C ${40}^{\circ }$

Given, $\angle ABC={20}^{\circ }$
We know that, angle subtended at the centre by an arc is twice the angle subtended by it at the remaining part of the circle.
$\angle AOC=2\angle ABC=2\times {20}^{\circ }={40}^{\circ }$

Therefore, option c is correct.