### Home > CALC > Chapter 7 > Lesson 7.3.1 > Problem 7-112

7-112.

Since there are 16 layers of cake, and 16 is a large number, it would be beneficial to write the Riemann sum in sigma notation:

Δ*x* represents the height of each cylindrical layer of cake.

Figure out the radius of the smallest layer. This will give you the initial value *a*.

No need to expand. Use a calculator to evaluate the sigma notation.