The sides BA and DE of a regular pentagon are produced to meet at F. What is the measure of ∠EFA?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 36º
Concept
Interior Angle of a polygon = 360º / No. of sides of polygon
Interior angle of pentagon = 360º / 5 = 108º
Application
AF is a straight line.
∠BAE + ∠EAF = 180°
∠EAF = 180° - 108°
∠EAF = 72°
Similarly
∠AEF = 72°
In triangle AEF
∠AEF + ∠EAF + ∠EFA = 180°
∠EFA = 180° - 72° - 72°
∠EFA = 36°