Question

Two angles measure $(30-a{)}^0$ and $(125+2a{)}^0$. If each one is the supplement of the other, then the value of a is :

• A. ${45}^0$
• B. ${35}^0$
• C. ${25}^0$
• D. ${65}^0$

Answer 1

The correct option is C ${25}^0$

If angles are supplement then their sum is ${180}^{\circ }$

$\therefore 30-a+125+2a={180}^{\circ }\Rightarrow 155+a={180}^{\circ }\Rightarrow a={180}^{\circ }-{155}^{\circ }\Rightarrow a={25}^{\circ }$