SOLUTION: Find the area of a regular pentagon with sides 7 millimeters long and apothem 4.8 mm long. (A=1/2aP) Please help

Algebra ->  Surface-area -> SOLUTION: Find the area of a regular pentagon with sides 7 millimeters long and apothem 4.8 mm long. (A=1/2aP) Please help      Log On


   

Question 161346: Find the area of a regular pentagon with sides 7 millimeters long and apothem 4.8 mm long. (A=1/2aP) Please help
Answer by jojo14344(1513) About Me  (Show Source):
You can put this solution on YOUR website!

Okay, you've given the AREA=%281%2F2%29aP---------> EQN 1
where a=side; P=apothem
This is a formula in finding the Area for a RIGHT triangle. Good Start! We know too the side is cut into half extending a line to the center (apothem) to make the triangle right? So we'll use a=%281%2F2%29a=%281%2F2%297mm=3.5mm to EQN 1.
.
Now, A=%281%2F2%29%283.5%29%284.8mm%29
A=8.4mm%5E2, ONLY for 1 triangle, but there are highlight%2810%29 triangles in a regular pentagon. So,
A=8.4mm%5E2%2A10=84mm%5E2 ANSWER
* See www.math-prof.com
Thank you,
Jojo