Find the volume of "A tetrahedron with three mutually perpendicular faces and three mutually perpendicular edges with lengths 3 cm, 4 cm, and 5cm."(adsbygoogle = window.adsbygoogle || []).push({});

This is how I visualized it:

http://img282.imageshack.us/img282/9466/calculus31re.th.jpg [Broken]

The area of a triangle along the x-axis is:

A(x) = .5 * x * (3/5x), 3/5x is from similar triangles.

A(x) = 3/10 * x^{2}

[tex]V = \int^{5}_{0} A(x) dx = \frac{3}{10} \int^{5}_{0} x^2 dx

= \frac{1}{10} [x^3]^{5}_{0}

= 12.5 cm^3[/tex]

But the answer is 10 cm^{3}. Why doesn't my method work?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Volume of a tetrahedron

**Physics Forums | Science Articles, Homework Help, Discussion**