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:
- n = 8
- l = 13
- a = 15.69
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)