We can change this shape into two easier shapes to deal with: 2 semi circles and 1 rectangle.
Now, we see that 2 semi circles is equal to one circle. So, let's first calculate the area of the circle. That is pi(r^2), which in this case is 16pi. (I got the radius from half of 8)
Now, what about the rectangle? We know that the width is 8...but what about the length? Well, it's not 18! As you see, we need to subtract 2r, which is 8, from 18. This gives us 10. So, 8(10) is 80.
Now, adding the two areas together, we get 80+16pi.