Question

Each interior angle of a regular polygon is 135°. Then find out how many diagonals are there?

A 25 Correct Answer Incorrect Answer
B 20 Correct Answer Incorrect Answer
C 30 Correct Answer Incorrect Answer
D 24 Correct Answer Incorrect Answer

Solution

Interior angle of polygon = 135° So exterior angle of regular polygon = 180° - 135° = 45° Then total side of polygon = (360°)/(exterior angle) = (360°)/(45°) Total side = 8 Then total Diagonals = n(n - 3)/2 {Where n = side} = (8×5)/2 = 20 Diagonals .

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