- A4
- B10
- C6
- D5
Step-by-Step Solution
Number of sides = 360 / 72 = 5. A regular polygon with 5 sides is a regular pentagon.
Answer: D) 5
An exterior angle of a regular polygon is 72°. How many sides does the polygon have?
Class 8Understanding QuadrilateralsQuadrilaterals
Key idea: Sum of exterior angles
**The sum of the exterior angles of any convex polygon (one at each vertex) is always 360°** — no matter how many sides.
For a regular n-gon, each exterior angle = 360°/n. So a regular quadrilateral (square) has exterior angle 360/4 = 90°. A regular pentagon: 72°. A regular hexagon: 60°.
For a regular n-gon, each exterior angle = 360°/n. So a regular quadrilateral (square) has exterior angle 360/4 = 90°. A regular pentagon: 72°. A regular hexagon: 60°.
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