Math CentralQuandaries & Queries


Question from Peter:

I'm building a dry stack stone wall which is 36” wide at the base, 42” tall and 24” wide at the top. What would be the volume for a 36” long segment ?
Thanks, Peter

Hi Peter,

The shape of the cross section of your wall is a trapezoid.


The area of a trapezoid is the average of the lengths of the parallel sides, times the distance between the parallel sides In your case that's

\[\frac{36 + 24}{2}\times 42 \mbox{ square inches.}\]

To calculate the volume of a section of the wall in cubic inches multiply the cross section area by the length in inches, in your case 36 inches.


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