http://www.ck12.org Chapter 11. Surface Area and Volume
Example 3:Find the surface area of the regular pentagonal prism.
Solution:For this prism, each lateral face has an area of 160units^2. Then, we need to find the area of the regular
pentagonal bases. Recall that the area of a regular polygon is^12 asn. s=8 andn=5, so we need to finda, the
apothem.
tan 36◦=4
a
a=4
tan 36◦≈ 5. 51
SA= 5 ( 160 )+ 2
(
1
2
· 5. 51 · 8 · 5
)
= 1020. 4
Cylinders
Cylinder:A solid with congruent circular bases that are in parallel planes. The space between the circles is enclosed.
Just like a circle, the cylinder has a radius for each of the circular bases. Also, like a prism, a cylinder can be oblique,
like the one to the right.