Regular tetrahedron/Introductory problem

Revision as of 19:30, 30 December 2012 by N1000 (talk | contribs) (Solution)
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Problem

Find the volume of a tetrahedron whose sides all have length $2$.

Solution

We find the area of the base:

$\mathrm {A} =\dfrac{4\sqrt{3}}{4}=\sqrt{3}$

Now we find the lateral height:

$\mathrm {lh}=\sqrt{2^2-1^2}=\sqrt{3}$

Now we can find the height of the tetrahedron:

$\mathrm {h}=\sqrt{(\sqrt{3})^2-(\dfrac{1}{3}*\sqrt{3})^2}=\sqrt{\dfrac{8}{3}$ (Error compiling LaTeX. Unknown error_msg)

Now the volume of the tetrahedron is:

$\dfrac{1}{3}*\sqrt{3}*\sqrt{\dfrac{8}{3}}=\dfrac{\sqrt{8}}{3}$


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