Question

If $OC$ & $OD$ are the bisectors of $\angle C$ & $\angle D$ respectively and $\angle A={115}^o$, find $\angle B$.

Answer 1

If OC and OD are bisectors

then $\angle ADC={35}^o\ast 2={70}^o$

and $\angle BCD={45}^o\ast 2={90}^o$

Since,Sum of all the interior angles in a Quadrilateral is ${360}^o$

${90}^o+{70}^o+{115}^o+\angle ABC={360}^o\Rightarrow \angle ABC={85}^o$