we have that
The area of the composite figure is equal to the area of a rectangle plus the area of a right triangle
so
step 1
Find out the area of the rectangle
A=L*W
A=8*5
A=40 cm2
step 2
Find out the area of the right triangle
A=(1/2)(b)(h)
where
b=8-(2+1)=8-3=5 cm
h=5 cm
A=(1/2)(5)(5)
A=12.5 cm2
therefore
the total area is
A=40+12.5=52.5 cm2
52.5 cm2