Question

If two angles in a $\Delta$ are ${65}^{\circ }$ and ${85}^{\circ },$ then the third angle is:

• A. ${30}^{\circ }$
• B. ${45}^{\circ }$
• C. ${60}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is A ${30}^{\circ }$

$\because$ Sum of the angles in a $\Delta ={180}^{\circ }$
i.e., ${65}^{\circ }+{85}^{\circ }+x={180}^{\circ }\Rightarrow x={30}^{\circ }$
$\therefore$ Third angle $={30}^{\circ }$.