Question

In $△PQR,\angle P={70}^o$ and $\angle R={30}^o$. Which side of this triangle is longest? Give reason for your answer.

Answer 1

In $△PQR,\angle P={70}^o,\angle R={30}^o$
But $\angle P+\angle Q+\angle R={180}^o$
${100}^o+\angle Q={180}^o$
$\angle Q={180}^o-{100}^o={180}^o$
$\angle Q={80}^o$ the greatest angle
Its opposite side $PR$ is the longest side
(side opposite to greatest angle is longest)