How do you find the volume of a solid using semi-circle cross-sections? What is the equation?

You can use the definite integral to find the volume of a solid with specific cross sections on an interval, provided you know a formula for the region determined by each cross section. If the cross sections generated are perpendicular to the x‐axis, then their areas will be functions of x, denoted by A(x). The volume ( V) of the solid on the interval [ a, b] is

Maybe you could explain your question better or give a proper example because I do not understand what you mean.