Question

If $ABCD$ is a cyclic quadrilateral such that $\angle A={90}^{\circ },\angle B={70}^{\circ }$ and $\angle C={90}^{\circ }$, then $\angle D$ in degrees is:

Answer 1

Here, $ABCD$ is a cyclic quadrilateral.

The sum of either pair of opposite angles of a cyclic quadrilateral is ${180}^{\circ }$.

Also, $\angle B+\angle D={180}^o$

$⟹{70}^o+\angle D={180}^o$

$⟹\angle D={180}^o-{70}^o={110}^{\circ }$.

Hence, $\angle D={110}^o$.