Skip to content

Physics Playground

Simulations How we teach Pricing

Language

Log in Start learning free

Loading…

Physics Playground

Built on open, peer-reviewed sources: OpenStax, The Feynman Lectures on Physics, HyperPhysics, NASA and NIST. See our sources.

Learn

Physics course
Math for Physics
Start with the math toolkit
Simulations
Glossary
Exercises
Past exams
Library
How we teach

Company

Pricing
Terms
Privacy
Contact

© 2026 Physics Playground. Made for the curious.Language

Exercises Graphs and straight lines

Example 11.44 from Prealgebra, 11.4 Understand Slope of a Line

Understand Slope of a Line: example 11.44

Sewage pipes must slope down $\frac{1}{4}$ inch per foot in order to drain properly. What is the required slope?

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Solution

Use the slope formula. $m = \frac{rise}{run}$

$m = \frac{- \frac{1}{4} in .}{1 ft}$

$m = \frac{- \frac{1}{4} in .}{1 ft}$

Convert 1 foot to 12 inches. $m = \frac{- \frac{1}{4} in .}{12 in.}$

Simplify. $m = - \frac{1}{48}$

The slope of the pipe is $- \frac{1}{48} .$

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Find the slope of the pipe: The pipe slopes down $\frac{1}{3}$ inch per foot.

How did it go?

PreviousUnderstand Slope of a Line: example 11.43 Next Use the Rectangular Coordinate System: example 4.1

From Prealgebra (1st edition) by OpenStax (Rice University), section 11.4, licensed under CC BY 4.0. Original at openstax.org. We split the solution into steps; the words, numbers and figures are the book's. OpenStax doesn't endorse this site.