Math CentralQuandaries & Queries


Question from RANDY, a parent:

I have an area of roof. It's in a sort of triangle.
it's 25' across the top
30' at each edge
86' across the bottom

Hi Randy. I tried to consider a roof where the edges were 30', but if
the bottom is 86' long, I think the 30' at each edge is the
measurement perpendicular to the top and bottom edges.

Here's a diagram of what I mean:


This shows a trapezoidal roof. The area of a trapezoid is the average of the top and bottom lengths times the height.

So your roof is (86 + 25) / 2 x 30 = 915 square feet.

If we have misinterpreted your description let us know.

Stephen La Rocque.

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