From the figure, what is the value of x?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 70°
An exterior angle of a triangle equals the sum of the two interior opposite angles. Angle ACD (120°) is the exterior angle at C, so it equals the angles at A and B together.
Exterior angle at C: \(50^\circ+x=120^\circ\)
So the angle at B is \(x=70^\circ\)