52 is the answer I believe
I will tell you use a calculator and leave the answer there. Try the math see if you get it correct. If you don't tell me!
Answer:
C. 647 square units
Step-by-step explanation:
To find the shaded area, subtract the area of the unshaded square from the area of the octagon.
<u>Area of the octagon</u>

where:
- n = number of sides
- l = length of one side
- a = apothem
Given:
Substitute the given values into the formula and solve for A:



<u>Area of the square</u>

<u>Area of the shaded region</u>
= area of the octagon - area of the square
= 815.88 - 169
= 646.88
= 647 square units (nearest square unit)