Question

In a triangle, two exterior angles are given by ${56}^{\circ }$ and ${136}^{\circ }$. Find the third exterior angle.

• A. ${178}^{\circ }$
• B. ${148}^{\circ }$
• C. ${158}^{\circ }$
• D. ${168}^{\circ }$

Answer 1

The correct option is D ${168}^{\circ }$

Let x be the third exterior angle .

"Sum of all the exterior angles in a triangle equal to ${360}^{\circ }$ "

So, we have:

x+ ${56}^{\circ }$ +${136}^{\circ }$ = ${360}^{\circ }$

$\Rightarrow$ x+ ${56}^{\circ }$ +${136}^{\circ }$ = ${360}^{\circ }$

$\Rightarrow$ x+ ${192}^{\circ }$ = ${360}^{\circ }$

$\Rightarrow$ x = ${360}^{\circ }$ - ${192}^{\circ }$ =${168}^{\circ }$