Answered

Polygons

Find the area of a regular decagon with an apothem of 8 meters and a side length of 5.2 meters.

Area: ______ m²



Answer :

To find the area of a regular decagon with an apothem of 8 meters and a side length of 5.2 meters, we can follow these steps:

1. Identify the properties of the decagon:
- A decagon is a polygon with 10 equal sides and 10 equal angles.
- The apothem is the perpendicular distance from the center to a side.

2. Calculate the perimeter of the decagon:
- The perimeter [tex]\( P \)[/tex] of a polygon is the sum of the lengths of all its sides.
- Here, the length of each side is 5.2 meters, and since a decagon has 10 sides, we calculate the perimeter as:
[tex]\[ P = 10 \times 5.2 = 52 \text{ meters} \][/tex]

3. Use the formula for the area of a regular polygon:
- The general formula for the area [tex]\( A \)[/tex] of a regular polygon is:
[tex]\[ A = \frac{1}{2} \times \text{apothem} \times \text{perimeter} \][/tex]
- Substituting the given values:
[tex]\[ A = \frac{1}{2} \times 8 \times 52 \][/tex]

4. Perform the multiplication and division to find the area:
- First, multiply the apothem by the perimeter:
[tex]\[ 8 \times 52 = 416 \][/tex]
- Then, divide by 2 to find the area:
[tex]\[ A = \frac{416}{2} = 208 \text{ square meters} \][/tex]

Therefore, the area of the regular decagon is [tex]\( 208 \, \text{m}^2 \)[/tex].