Posted by **Emily** on Thursday, September 27, 2007 at 9:04pm.

In a regular polygon (equal sides and angles), you use (n-2)180 to find out what the interior angle sum is (n=number of sides in polygon) and you divide by that number by whatever n is to find out the measure of an individual angle, right? Well, there is going to be a problem on tomorrow's geometry test where we are given the measure of an interior angle of a regular polygon (for instance, one angle=150 degrees), but I can't tell how to do that. I figured it would be something like this:

(n-2)180

-------- = 150

n

But, it dosn't work out too well when I try to single out n. Can someone tell me how to do this?

P.S. Sorry that my explanation was so long -- I was trying to get the information out there :-) THANKS!!!

- Geometry -
**bobpursley**, Thursday, September 27, 2007 at 9:12pm
Take an interior angle: 150 degrees. How many sides?

the sum of interior angles is 150n (n angles, each 150 degrees)

but (n-2)180= 150n (both are sum of interior angles, and equal, so

180n-360=150n

30n=360

n= 12

\thats it.

- Geometry -
**Emily**, Thursday, September 27, 2007 at 9:18pm
Oh -- I get it! Thank you so much for helping me out, I really needed that info for tomorrow's test. Thx!

- Geometry -
**Colleen**, Wednesday, April 15, 2009 at 5:04pm
i have absolutely no idea how to do this!

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