Question

10 numeric 10 points what is the degree measure of angle 1? (enter the numeric value only)

Explanation:

Step1: Find angle 5

Since an exterior - angle and its adjacent interior - angle are supplementary, if the exterior angle is 125°, then $\angle5=180 - 125=55^{\circ}$.

Step2: Use the angle - sum property of a triangle

The sum of the interior angles of a triangle is 180°. In the triangle with angles 1, 40°, and 5, we know that $\angle1+40^{\circ}+\angle5 = 180^{\circ}$.
Substitute $\angle5 = 55^{\circ}$ into the equation: $\angle1+40^{\circ}+55^{\circ}=180^{\circ}$.

Step3: Solve for angle 1

$\angle1=180-(40 + 55)$.
$\angle1=180 - 95$.
$\angle1 = 85^{\circ}$.

Answer:

85