Use the exponential function of f(x)= 100x times (1.08)^2
62.8cm^2 I think that's the answer
At first find the area of rectangle:
(x + 4)*(x + 1) = x^2 + 5x + 4
Then find the area of triangle:

Then you must do like this
Area of rectangle - Area of triangle = Area of the shaded
x^2+5x+4 - (

)