Question

What is the measure of Angle D F E?

Answer 1

Given:

Given that the measure of the exterior angle F is 142°

We need to determine the measure of ∠DFE

Measure of ∠DFE:

The ∠DFE and the exterior angle F are linear pairs.

Thus, the linear pair of angles add up to 180°

Hence, we have;

$\angle DFE+142^{\circ}=180^{\circ}$

Subtracting both sides of the equation by 142, we get;

$\angle DFE=38^{\circ}$

Hence, the measure of ∠DFE is 38°

Thus, Option a is the correct answer.