# Calculate the Number of Sides of a Regular Polygon, If: Its Exterior Angle Exceeds Its Interior Angle by 60°. - Mathematics

Sum

Calculate the number of sides of a regular polygon, if: its exterior angle exceeds its interior angle by 60°.

#### Solution

Let interior angle = x

Then exterior angle = x + 60

∴ x + x + 60° = 180°

⇒ 2x = 180° - 60° = 120°

⇒ x = (120°)/2 = 60°

∴ Exterior angle = 60° + 60° = 120°

∴ Number of sides = (360°)/(120°) = 3

Concept: Regular Polynomial
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#### APPEARS IN

Selina Concise Mathematics Class 8 ICSE
Chapter 16 Understanding Shapes
Exercise 16 (B) | Q 19.3 | Page 185