### Home > CALC > Chapter 8 > Lesson 8.3.2 > Problem 8-109

8-109.

Given that a typical cross-section of a solid taken perpendicular to the *x*-axis has an area of *A*(*x*) = ln *x*, set-up an integral to calculate the volume of this solid from [*a, b*]. Does it matter what the shape of the solid is? Explain. Homework Help ✎

Of course every shape has a different area function, and this area function = ln*x*.

It is not possible to know what the cross-sections looks like. Perhaps they are rectangles with height = ln*x* and base = 1? But they could also be strange looking shapes. Just as long as all of their areas = (coefficient)(base)(height) = ln*x*, the Volume by Cross Section formula will work.