Geometry and TrigonometryEasyExterior angle of an equilateral triangle
Geometry and Trigonometry practice question
Each interior angle of an equilateral triangle measures 60°. What is the measure, in degrees, of an exterior angle at one of its vertices?
Answer: 120
An exterior angle and its interior angle add to 180: 180 − 60 = 120.
Common wrong answers
- If you answered 60
- 60 is the interior angle.
- If you answered 240
- 240 doubles 120.
- If you answered 300
- 300 subtracts from 360.
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