Steve wants to make a triangular pyramid with 4 faces. He takes 4 isosceles triangles and tapes them together. Each triangle is 4 inches wide at the bottom. The altitude of each triangle is 9 inches. What is the total area of the 4 triangular faces?

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Answer 1 · 2017-10-26T09:27:57

72"

Area of an isoceles triange is #(b*h)/2#
Where b is the base length
h is the height
and 2, is well... 2.

So plug in values

4*9 = 36
divided by 2 is 18.

There are 4 of them so times 18 by 4, which gives 72 inches.