# Pizza & Cola

## Prompt

** “Which of the graphs below…” **

## Context

This SWBQ provides an easy introduction to the graphical representation of functions of several variables.

## Wrap Up

In each case, a brief discussion consists of asking for a student volunteer to describe how the shape of each graph is related to the corresponding prompt. Common answers typically analyze where the graphs are increasing or decreasing separately in the pizza and cola directions.

*This question is taken from Calculus, 4th edition, by Hughes Hallett et
al, © 2005 by John Wiley & Sons, Inc, and is used by permission.*