Question

Two angles of a triangle are of measures 105° and 30°. Find the measure of the third angle.

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{the}\mathrm{third}\mathrm{angle}\mathrm{be}\mathrm{x}. \\ \mathrm{Sum}\mathrm{of}\mathrm{all}\mathrm{the}\mathrm{three}\mathrm{angles}\mathrm{of}\mathrm{a}\mathrm{triangle}=180° \\ \therefore 105°+30°+\mathrm{x}=180° \\ \mathrm{or},\mathrm{x}=180°-135° \\ \therefore \mathrm{x}=45° \\ \mathrm{The}\mathrm{third}\mathrm{angle}\mathrm{is}45°. \end{gathered}$$