Posted by **Guru** on Monday, February 4, 2013 at 5:36pm.

In a regular polygon,each interior angle doubles its corresponding exterior angle,find the number of side of the polygon?

- Maths -
**Reiny**, Monday, February 4, 2013 at 6:15pm
let the exterior angle be

a , b, c , d, e ....

then the interior angles are

2a , 2b, 2c, ...

we know a+b+c+.. = 360

suppose we have n sides

sum of interior angles = 180(n-2)

so 2a + 2b + 2c + ... = 180(n-2)

2(a+b+c+.. = 180(n-2)

but a+b+c+..=360

2(360) = 180(n-2)

4 = n-2

n = 6

There are 6 sides

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