You are told the middle part is a square, so all 4 sides are equal.
The height is shown as 4 feet, so the width of the square is also 4 feet.
This means the height of the 2 triangles is 7 - 4 = 3 feet, so each triangle is 1.5 feet high ( 3 feet / 2 = 1.5).
The area of the square is 4 x 4 = 16 square feet.
The area of 1 triangle is 1/2 x base x height = 1/2 x 4 x 1.5 = 3 square feet.
The total area = 16 + 3 + 3 = 22 square feet.
