ACT Math : How to find the length of an edge of a polyhedron

Study concepts, example questions & explanations for ACT Math

varsity tutors app store varsity tutors android store

Example Questions

Example Question #1 : How To Find The Length Of An Edge Of A Polyhedron

If we have a regular (the triangles are equilateral) triangular prism of volume  and the side length of the triangle on either face is , what is the length of the prism? Write your answer in terms of a decimal rounded to the nearest hundredth.

Possible Answers:

Not enough information to decide.

Correct answer:


The volume of a triangular prism can be simply stated as V = A*L, where A is the area of the triangular face and L is the length. We have the volume already and we need to figure out the area of the triangle from the side length.

The area of a triangle is b*h/2, and we are given the base/side length: 3 in. We also have a formula for the height of an equilateral triangle, . Calculating the area of the triangle we get 2.5981 in^2, so now we just have to plug our numbers into the volume formula.

And that is the final answer.

Learning Tools by Varsity Tutors

Incompatible Browser

Please upgrade or download one of the following browsers to use Instant Tutoring: