# Thread: Areas of Regular Polygons

1. ## Areas of Regular Polygons

I need help with a math problem (yes its for school i dont need the answer just some direction as my book doesnt explain some stuff very well)

Ok, i need to find the area of a regular pentagon with perimeter 60 and apothem X.

Area = 1/2 apothem*perimeter

first you need to make a right triangle out of this. Area of regular polygons has to be done as if circumscribed in a circle.

Mathgirl32 i need you ! :P

2. ## Q

Um, I don't really know or remember what an apothem is. If you can tell me than I can probably help you. By the way I searched on Google for what an Apothem was. I haven't found a source that told me what one was for a pentagon but I did come across a site that might help you. Here is a link to their FAQ. Thats all I can do for now.

3. I hate geometry, especially trig. I didn't feel like figuring this one out on my own (it's 5:00 AM) so here.
http://www.mpa.candler.nc.us/organiz...ry/Chp10-5.htm
This should explain everything you need to know. If you have anymore questions, ask. I'll answer them in the morning. Zzz....

4. http://www2.edc.org/mathproblems/pro...ekPentForm.pdf
that seems to have a few answers

5. The way I remember it is that every regular polygon can be split into a number of triangles equal to the number of sides in the polygon (in this case, 5). Since you know the length of one of the sides (60/5 = 12) and the angle between each side (540 angles in a pentagon, divided by 5 is 108).

To calculate the angles in a regular polygon, just take the number of sides, subtract two and multiply your answer by 180 (working in degrees here, not radians).

Hope this helps.

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