The figure is composed by a square and 4 triangles:
We have to find the area of the square, the area of the 4 triangles, and add them.
Area of a square: side lenght ^2
side length = 4
A1 = 4^2 = 16 square units
Then, find the area of a triangle:
A = 1/2 x base length x height
base length =2
height = 1
Replacing:
A2 = 1/2 x 2 x 1 = 1 square unit
Since the triangles are equal, we can multiply the area by 4, to obtain the area of the 4 triangles:
1 x 4 = 4 square units
Add the area of the square and the area of the 4 triangles:
16 +4 = 20 square units
