Question

d. x = ____ 40° 130° x

Explanation:

Step1: Recall exterior - angle property

The exterior - angle of a triangle is equal to the sum of the two non - adjacent interior angles.

Step2: Set up the equation

Let the exterior angle be $130^{\circ}$, and the two non - adjacent interior angles be $x$ and $40^{\circ}$. So, $x + 40^{\circ}=130^{\circ}$.

Step3: Solve for $x$

Subtract $40^{\circ}$ from both sides of the equation: $x=130^{\circ}-40^{\circ}$.
$x = 90^{\circ}$

Answer:

$90^{\circ}$