Q13
ArithmeticGeometry & Mensuration
The ratio of measurement of an interior angle and an exterior angle of a polygon is 3:2. The number of sides of a polygon is
- a.5
- b.10
- c.15
- d.20
Answer: (A) 5
Interior and exterior angles add up to $180^\circ$, so in the ratio 3 : 2 the exterior angle is $72^\circ$. The number of sides is $360^\circ \div 72^\circ = 5$. A 10-sided polygon would have exterior angles of $36^\circ$, giving a ratio of 4 : 1.