Questions on Geometry: Bodies in space, right solid, cylinder, sphere answered by real tutors!

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Question 145658: Find the length, to the nearest tenth, of the apothem of a regular octagon whose sides are 10 inches long?????: Find the length, to the nearest tenth, of the apothem of a regular octagon whose sides are 10 inches long?????
Answer by nerdybill(1283) About Me  (Show Source):
You can put this solution on YOUR website!
For a detailed explanation of apothem and octagon see:
http://www.mathsisfun.com/geometry/regular-polygons.html
.
Use radians NOT degrees...
.
Side = 2 × Radius × sin(π/n)
where
n = number of sides
.
Stuff in the information from the problem:
10 = 2 × Radius × sin(π/8)
5 = Radius × sin(π/8)
5/sin(π/8) = Radius
.
Then, because
Apothem = Radius × cos(π/n)
Apothem = 5/sin(π/8) × cos(π/8)
Apothem = 5cos(π/8)/sin(π/8)
Apothem = 5cos(π/8)/sin(π/8)