### Home > CALC > Chapter 7 > Lesson 7.1.2 > Problem 7-23

7-23.

Recall that a Riemann sum is a sum of the area of many rectangles.

Sigma notation is a tool to concisely write that sum, but it is not essential that you use sigma notation.

In order for Kiki to have enough cake to feed her guests, the total volume of all 4 layers of cake should exceed 7(200) = 1400 cubic inches.