Mathematics: A B C or D

What is the perimeter of a regular octagon with an area of 286.36 cm2 and an apothem of length 9.3 cm?

A)63.5cm
B)66.7cm
C)68.3cm
D)61.6cm

Hey there, hi there, ho there,

Area of a regular polygon is given by A=(1/2)aP where A is the area, a is the apothem, and P is the perimeter.

We have A=286.36 and a=9.3. Plug these in:

286.36=(1/2)(9.3)P

Simply multiply by 2 and divide by 9.3.

We get P=61.6 cm when rounded.

Choice D is the correct alternative.