The rectangle has the dimensions 4 x 3.
The measure of 6 ft is the triangle plus the square's length.
The rectangle's length is 3.
To find the triangle's width, solve this: 3 + x = 6
Subtract 3 from each side to get x = 3.
The dimensions of the triangle is 3 x 4.
The area will be half of 3 x 4, so 12 / 2 or 6.
The rectangle's area is 12 because its dimensions are 3 x 4.
12 + 6 = 18 feet total.
Hope this helps!