Option C:
x = 30
Solution:
The given image is a triangle.
angle 1, angle 2 and angle 3 are interior angles of a triangle.
angle 4 is the exterior angle of a triangle.
m∠4 = 2x°, , m∠3 = 20°
Exterior angle theorem:
<em>In triangle, the measure of exterior angle is equal to the sum of the opposite interior angles.</em>
By this theorem,
m∠4 = m∠2 + m∠3
Subtract on both sides of the equation.
To make the denominator same and then subtract.
Multiply by on both sides of the equation.
x° = 30°
x = 30
Hence option C is the correct answer.