Question

Find the area of an octagon whose perimeter is 120 cm.

Answer 1

Answer:

The area of an octagon whose perimeter is 120 cm is 1086.4 $cm^{2}$

Step-by-step explanation:

An octagon is a polygon with eight sides. If the lengths of all the sides and the measurement of all the angles are equal, the octagon is called a regular octagon.

There is a predefined set of formulas for the calculation of perimeter, and area of a regular octagon.

The perimeter of an Octagon is given by

$P=8a$

and the area of an Octagon is given by

$A=2a^{2}(1+\sqrt{2})$

We know that the perimeter is 120 cm, solving for side length (a) in the perimeter formula we get

$120=8a\\\frac{8a}{8}=\frac{120}{8}\\a=15$

Now, we calculate the area

$A=2a^{2}(1+\sqrt{2})\\A=2(15)^{2}(1+\sqrt{2})\\A=450\left(1+\sqrt{2}\right)\\A\approx 1086.4 \:cm^{2}$