To find the area of the arrow you sum the area of the square and the area of the triangle:

Area of a square:

s is the measure of one side of the square
Area of a triangle:

b is the measure of the base and h is the height of the triangle.
Then, the area of the arrow is:

s= 3ft
b= 3ft+2.5ft+2.5ft=8ft
h=5ft

Then, the area of the arrow is 29 square feet