Question

If $\angle A=30°$ and $\angle B=60°$ in $∆ABC$, then measure $\angle C$.

Answer 1

As we know that sum of all three angles of triangle is $180°$

So,

$$\begin{gathered} \Rightarrow \angle A+\angle B+\angle C=180° \\ \Rightarrow 30°+60°+\angle C=180° \\ \Rightarrow 90°+\angle C=180° \\ \Rightarrow \angle C=180°-90° \\ \Rightarrow \angle C=90° \end{gathered}$$

Hence $\angle C=90°$