Posted by **polygon** on Wednesday, March 28, 2012 at 1:43am.

each interior angle of a regular polygon is 18 degree more than eight times an exterior angle. the number os sides of polygon is.

- maths -
**Steve**, Wednesday, March 28, 2012 at 11:14am
at each vertex, interior + exterior = 180 degrees.

If exterior = x,

x+(8x+18) = 180

9x = 162

x = 18

he exterior angle of a regular n-gon is 360/n, so

18 = 360/n

n = 20

- maths -
**drwls**, Wednesday, March 28, 2012 at 11:22am
Interior angle = 180 - (exterior angle) = 180 -360/N

Exterior angle = 360/N

180 - (360/N) = [8*360/N] +18

9*360/N = 162

N = 20 sides

It is called an icosagon

## Answer This Question

## Related Questions

- math--fast help please - Find the interior and exterior angle measurements of a ...
- geometry - If the ratio of the interior angle to the exterior angle is 5:1 for a...
- math. - Each exterior angle of a regular polygon is 15 degrees. 1.Determine the ...
- please help!!!!! someone - Each exterior angle of a regular polygon is 15 ...
- Math - Are the statements Always, Sometimes or Never. Please explain why. Thanks...
- math - The size of an interior angle of a regular polygon is 3x° while its ...
- Maths - In a regular polygon,each interior angle doubles its corresponding ...
- Geometry - 1. How many sides does a regular polygon have if one exterior angle ...
- Maths - A regular polygon has an interior angle which less than ten times its ...
- maths - Give reasons 1) Every parallelogram is not a rectangle. 2) Every ...

More Related Questions