step 1
Find the area
we have that
the area of the figure is equal to the area of a rectangle plus the area of a triangle
so
A=(20*15)+(1/2)(15)(8)
A=300+60
A=360 ft^2
area is 360 square feet
step 2
Find the perimeter
The perimeter of the figure is equal to sum three sides of the rectangle plus two sides of the triangle
so
P=15+20+20+8+17
P=80 ft
therefore
the perimeter is 80 feet