Find the area of the regular decagon if the apothem is 5 in. and a side is 3.2 in. Round to the nearest whole number.

160 in2

40 in2

65 in2

80 in2

1 answer

To find the area of a regular decagon, we can use the formula:

Area = (Perimeter * Apothem) / 2

First, we need to find the perimeter of the decagon. Since a decagon has 10 sides and each side is 3.2 inches long:

Perimeter = 10 * 3.2 = 32 inches

Now we can plug in the values into the formula:

Area = (32 * 5) / 2
Area = 160 in2

So, the area of the regular decagon with an apothem of 5 in. and a side of 3.2 in. is 160 in2. Rounded to the nearest whole number, the answer is 160 in2.

Therefore, the correct answer is: 160 in2.