16Hit1600
Geometry and TrigonometryHardFifth angle of a pentagon

Geometry and Trigonometry practice question

The interior angles of a pentagon have a sum of 540°. Four of the interior angles of a certain pentagon each measure 100°. What is the measure, in degrees, of the fifth angle?

Answer: 140

540 − 400 = 140.

Common wrong answers

If you answered 40
40 is 140 − 100.
If you answered 100
100 assumes all five angles are equal.
If you answered 108
108 is the angle of a regular pentagon.

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