Question

One of the angles of a triangle is 130°, and the other two angles are equal. What is the measure of each of these equal angles?

Answer 1

$$\begin{gathered} \mathrm{Let}\mathrm{the}\mathrm{other}\mathrm{two}\mathrm{angles}\mathrm{be}\mathrm{x}. \\ \mathrm{Sum}\mathrm{of}\mathrm{all}\mathrm{the}\mathrm{three}\mathrm{angles}\mathrm{of}\mathrm{a}\mathrm{triangle}=180° \\ \mathrm{i}.\mathrm{e}.130°+\mathrm{x}+\mathrm{x}=180° \\ \Rightarrow 2\mathrm{x}=180°-130° \\ \Rightarrow 2\mathrm{x}=50° \\ \Rightarrow \mathrm{x}=\frac{50°}{2} \\ \Rightarrow \mathrm{x}=25° \\ \mathrm{Therefore},\mathrm{the}\mathrm{other}\mathrm{two}\mathrm{angles}\mathrm{are}25°\mathrm{each}. \end{gathered}$$