Question

which of the following represents the exterior angle theorem for the triangle pictured?
$a + b + c = 180$
$d = a + c$
$b = a + c$
$d = 180 - b$

Explanation:

Step1: Recall exterior angle theorem

The exterior angle of a triangle equals the sum of the two non-adjacent interior angles.

Step2: Match to the triangle

For exterior angle $d$, non-adjacent interior angles are $a$ and $c$.

Answer:

B. $d = a + c$