Answer: 233.5 square miles
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Explanatoin:
There are a number of ways to do this type of problem. One way is to divide the figure as shown in the diagram below. See the attached image.
I'm splitting the irregular shape into two rectangles and a triangle.
The upper rectangle is 10 miles by 9 miles to get an area of 10*9 = 90 square miles. Let A = 90 so we can use it later.
The lower rectangle is 4 miles by 19 miles. Its area is 4*19 = 76 square miles. Let B = 76.
The total vertical height of the figure is 9+4+10 = 23 miles.
Notice along the column that has "8 miles" up top over "9 miles" down below, we have a gap of some distance which I'll call x. This x adds to 8 and 9 to get the 23 mentioned.
x+8+9 = 23
x+17 = 23
x = 23-17
x = 6
This helps find the height of the triangle which is 9+x = 9+6 = 15 miles.
The triangle has a base of 9 miles.
The area of the triangle is base*height/2 = 9*15/2 = 135/2 = 67.5 square miles. Let C = 67.5
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We found that:
- A = 90 = area of the upper rectangle
- B = 76 = area of the lower rectangle
- C = 67.5 = area of the triangle
The total area is: A+B+C = 90+76+67.5 = 233.5 square miles.