Question

In the given figure, if $\angle AOC$ = 65°, then $\angle COB$ = ___.

• A. ${115}^{\circ }$
• B. ${65}^{\circ }$
• C. ${25}^{\circ }$
• D. ${70}^{\circ }$

Answer 1

The correct option is A

${115}^{\circ }$

$\Rightarrow \angle AOC+\angle COB={180}^{\circ }........\left(anglesonastraightline\right)$

$\Rightarrow {65}^{\circ }+\angle COB={180}^{\circ }$

$\Rightarrow \angle COB=180-{65}^{\circ }={115}^{\circ }$