What is the measure of Angle D F E?
not drawn to scale

38 degrees
52 degrees
118 degrees
142 degrees

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;

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

Hence, the measure of ∠DFE is 38°

Thus, Option a is the correct answer.