Question

if $OCD$ is an isosceles triangle in which $OD$ and $OC$ are equal,and its included angle is ${40}^o$ then what will be the value of $\angle OCD$?

• A. ${70}^o$
• B. ${50}^o$
• C. ${65}^o$
• D. ${45}^o$

Answer 1

The correct option is A ${70}^o$

As It is Isosceles triangle with OC=OD,$\angle COD={40}^{\circ }$

So, $\angle OCD=\angle ODC$(Angle opposite to equal side are equal)

In $\Delta$OCD,using angle sum property

$\angle OCD+\angle ODC+\angle COD=180⟹2\angle OCD+40=180⟹2\angle OCD=140⟹\angle OCD={70}^{\circ }$