Answer:
1) 23.4 km²
2) 403.1 mi²
Explanation:
The formula for the area of a regular polygon is half the product of its apothem and perimeter.

From inspection of the given regular polygons, we have been given the perimeter or side length only. Therefore, we need to calculate the apothem.
The formula for the length of the apothem of a regular polygon is:

Question 1
The given polygon has 6 sides, and its perimeter is 18 km. Therefore:
Substitute the values of s and n into the apothem formula and solve for a:

To find the area of the polygon, substitute the found value of a, along with the perimeter, P = 18, into the area formula:

Therefore, the area of the regular polygon is 23.4 km² to the nearest tenth.

Question 2
The given polygon has 12 sides, and the length of one side is 6 miles. Therefore:
Substitute the values of s and n into the apothem formula and solve for a:

The perimeter of the polygon is n · 2 = 12 · 6 = 72 miles.
To find the area of the polygon, substitute the found value of a, along with the perimeter, P = 72, into the area formula:

Therefore, the area of the regular polygon is 403.1 mi² to the nearest tenth.