Question

Three angles of a quadrilateral $ABCD$ are $\angle A={70}^o,\angle B={50}^o$ and $\angle C={82}^o$. Find $\angle D$.

Answer 1

Angle sum of quadrilateral is ${360}^{\circ }$

$\angle A+\angle B+\angle C+\angle D={360}^{\circ }$

${70}^{\circ }+{50}^{\circ }+{82}^{\circ }+\angle D={360}^{\circ }$

$\angle D={158}^{\circ }$