To find the area of the composite figure formed by the three rectangles, we need to calculate the area of each rectangle individually and then sum these areas.
-
First Rectangle:
- Length: 3 mi
- Width: 1 mi
- Area = Length × Width = \(3 , \text{mi} \times 1 , \text{mi} = 3 , \text{mi}^2\)
-
Second Rectangle:
- Length: 1 mi
- Width: 1 mi
- Area = Length × Width = \(1 , \text{mi} \times 1 , \text{mi} = 1 , \text{mi}^2\)
-
Third Rectangle:
- Length: 3 mi
- Width: 7 mi
- Area = Length × Width = \(3 , \text{mi} \times 7 , \text{mi} = 21 , \text{mi}^2\)
Now, we add up the areas of all three rectangles:
\[ \text{Total Area} = \text{Area of Rectangle 1} + \text{Area of Rectangle 2} + \text{Area of Rectangle 3} \] \[ \text{Total Area} = 3 , \text{mi}^2 + 1 , \text{mi}^2 + 21 , \text{mi}^2 = 25 , \text{mi}^2 \]
Therefore, the total area of the composite figure is 25 square miles.