Question

http://www.rmes.us/AngelUploads/Content/MAT201//_assoc/Content/G%20Images/u2m8q2.jpg

If a regular octagon has an apothem approximately 7.2 in. long and a side 6 in. long, what is its approximate area?
A) 77 sq. in.
B) 172.8 sq. in.
C) 347.6 sq. in.
D) 302.4 sq. in.

Answer 1

please help!

Answer 2

i don't understand this!!

Answer 3

http://upload.wikimedia.org/wikipedia/commons/7/73/Apothem_of_hexagon.svg
the green line is an apothem

the formula you need is
\[Area =(nsa)/2\]
n = #of sides of polygon =8 in this case
a = length of apothem =7.2 in this cae
s = length of a side = 6 in this case

so A = 172.8

note this formula only works for regular polygons