In the given figure, ABCD is a square. Angle DEC = 65 degrees. What is the value (in degrees) of angle EFA?
Show answer & explanation
Correct answer: B
Explanation
Given:
ABCD is a square.
∠DEC = 65°
The sum of the angles of a triangle = 180°.
Alternate angles formed by parallel lines are equal.
The sum of angles on a straight line = 180°.
In triangle DEC:
∠EDC = 45° (Diagonal of the square)
∠EDC + ∠DEC + ∠DCE = 180°
45° + 65° + ∠DCE = 180°
∠DCE = 70°
Now, ∠BFC = ∠DCE = 70° (Alternate angles)
On the straight line AB:
∠EFA + ∠BFC = 180°
∠EFA + 70° = 180°
∠EFA = 110°