If a driveway has a curve in it how could I calculate the volume

Question

The question has a semi circular driveway but there is a smaller semi circle missing nd I need to find volume of concrete how do i do that 

 

Answer 1

The volume involved will be the surface area times a designated thickness.

 

Calculate the area of the semicircle and then subtract from that the area of the smaller semicircle.

Once you know this net area, you can multiply area times thickness to find the volume.

I believe that concrete is sold and delivered by the cubic yard, so watch your units!.