In a quadrilateral ABCD, angles A, B, C are in the ratio 1 : 2 : 3. If angle D = 120°, what is angle A?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 40°.
D = 120°
Sum of angles in a quadrilateral = 360°
⇒ A + B + C = 360° - 120° = 240°
Let A = x, B = 2x, C = 3x
x + 2x + 3x = 240°
⇒ 6x = 240°
⇒ x = 40°
⇒ A = 40°