In the given figure, angle BCD = 155 degrees and angle ABC = 85 degrees. What is the value (in degrees) of angle BAC?
Show answer & explanation
Correct answer: B
Explanation
∠BCD = 155°
∠ABC = 85°
According to the formula:
Exterior angle = 180° − Interior angle
Sum of the angles of a triangle = 180°
∠BCD is an exterior angle
∠ACB = 180° − 155° = 25°
In triangle ABC:
∠BAC + ∠ABC + ∠ACB = 180°
∠BAC + 85° + 25° = 180°
∠BAC = 180° − 110° = 70°