What is a simple formula for finding the volume of a triangular pyramid with a base side length of 18 and a height of 4?
please hurry!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
V=Bh
So it would be the area of the base times the heighth. I think the answer is 72units^2
@cdromdj: You second answer (the more recent one) seems to be correct, since we are finding volume.
The "formula" is ....... (1/3) * (Area of the base) * (Height)
The height is easy.
The area of the base is a little more complicated.
It's given by (√(3)/4)(s2), where s is the side length of the pyramid.
So we have (1/3) * (√(3)/4)(182) * (4) = (1/√(3))(324) = (324 / √(3)) ≈ 187.06 cubic units
I think CPhill has assumed that the base is an equilateral triangle of side length 18 units.
This is not actually stated in the question but i guess it is a reasonable assumption.
All the angels are 60 degrees
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in triangle ABC
Area=12×a×b×sinC
Area=12×18×18×sin60
Area=162×√32
Area=81×√3
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Volume=13×Area×height
Volume=13×81×√3×4
Volume=108×√3 units cubed.
Volume≈187unit3