# PSAT Math : How to find the volume of a tetrahedron

## Example Questions

### Example Question #253 : Psat Mathematics

Note: Figure NOT drawn to scale.

The above triangular pyramid has volume 25. To the nearest tenth, evaluate .

Insufficient information is given to answer the problem.

Explanation:

We are looking for the height of the pyramid.

The base is an equilateral triangle with sidelength 4, so its area can be calculated as follows:

The height  of a pyramid can be calculated using the fomula

We set  and  and solve for :

### Example Question #254 : Psat Mathematics

Note: Figure NOT drawn to scale.

Give the volume (nearest tenth) of the above triangular pyramid.

Explanation:

The height of the pyramid is . The base is an equilateral triangle with sidelength 4, so its area can be calculated as follows:

The volume of a pyramid can be calculated using the fomula

### Example Question #255 : Psat Mathematics

A regular tetrahedron has an edge length of . What is its volume?