- A60°
- B120°
- C180°
- D240°
Step-by-Step Solution
By the Exterior Angle Theorem, an exterior angle equals the sum of the two interior opposite angles, so they add up to 120°.
Answer: B) 120°
An exterior angle of a triangle is 120°. The two interior opposite angles add up to:
Class 9Angle Sum of a TriangleGeometry — Lines and Angles
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