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If the difference between the exterior and the interior angles of a regular polygon is 60o, with an interior angle being greater than the correspondin
Question

If the difference between the exterior and the interior angles of a regular polygon is 60o, with an interior angle being greater than the corresponding exterior angle, then find the number of sides of the polygon.

A.

7

B.

5

C.

6

D.

8

Correct option is C

Given:

Difference between interior angle and exterior angle = 60

Interior angle is greater than the exterior angle

We are to find the number of sides of the regular polygon

Concept Used:
For a regular polygon with n sides:

Exterior angle = 360n \frac{360^\circ}{n}​​

Interior angle = 180360n 180^\circ - \frac{360^\circ}{n}​​

Solution:

From the given condition;

(180360n)360n=60(180^\circ - \frac{360^\circ}{n}) - \frac{360^\circ}{n} = 60^\circ​​

180720n=60180^\circ - \frac{720^\circ}{n} = 60^\circ​​

720n=120\frac{720^\circ}{n} = 120^\circ​​

n=720120=6n = \frac{720}{120} = 6​​

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