Applying the alternate interior angles theorem, the measure of angle FBC is determined as: 67°.
What is the Alternate Interior Angles Theorem?
If two angles are alternate interior angles formed along a transversal on two parallel lines, then their measures are congruent or the same.
What are Angles on a Straight Line?
Angles on a straight line are angles that lie along a straight line, and the sum of the angles equals 180 degrees.
Given the following:
m∠BFC = 75°
m∠GFC = 38°
∠EFB, ∠BFC, and ∠GFC are angles on a straight line, therefore:
m∠EFB = 180 - m∠BFC - m∠GFC
Plug in the values
m∠EFB = 180 - 75 - 38
m∠EFB = 67°
Find the measure of angle FBC:
Angles FBC and EFB are alternate interior angles, therefore:
m∠FBC = m∠EFB = 67° [alternate interior angles theorem]
m∠FBC = 67°
In summary, using the alternate interior angles theorem, the measure of angle FBC is determined as: 67°.