The Math Forum

Ask Dr. Math - Questions and Answers from our Archives
Associated Topics || Dr. Math Home || Search Dr. Math

Comparing Volume and Surface Area

Date: 05/01/2002 at 12:13:58
From: Anonymous
Subject: Volume vs. surface area

Why is it that the surface area of a given rectangular solid can 
sometimes be greater than the volume of that solid?

Date: 05/01/2002 at 13:09:40
From: Doctor Peterson
Subject: Re: Volume vs. surface area


You can't really compare area and volume, since they use different 
units. It's like asking why I am sometimes older than my weight, and 
sometimes younger! (It depends on whether you use pounds or tons.) 
You really can't say that 50 years is less than 160 pounds, and you 
can't say that 50 cubic meters is less than 160 square meters.

Take a one-foot cube. Its volume is one cubic foot; its surface area 
is 6 square feet, which is numerically greater. But if I use inches, 
the volume is 12^3 = 1728 cubic inches, and its surface area is 
6*12^2 = 864 square inches, which is numerically smaller. If one 
object has its area sometimes smaller and sometimes greater than its 
volume, depending only on the units I use, the comparison doesn't 
mean anything, does it?

- Doctor Peterson, The Math Forum 

Date: 05/03/2002 at 11:47:23
From: Anonymous
Subject: Volume vs. surface area

It makes sense the way you put it... Thank you!
Associated Topics:
High School Higher-Dimensional Geometry
Middle School Higher-Dimensional Geometry
Middle School Measurement

Search the Dr. Math Library:

Find items containing (put spaces between keywords):
Click only once for faster results:

[ Choose "whole words" when searching for a word like age.]

all keywords, in any order at least one, that exact phrase
parts of words whole words

Submit your own question to Dr. Math

[Privacy Policy] [Terms of Use]

Math Forum Home || Math Library || Quick Reference || Math Forum Search

Ask Dr. MathTM
© 1994- The Math Forum at NCTM. All rights reserved.