Video:How to Find the Volume and Surface Area of a Triangular Prismwith Eric Stone
Our expert shows how to find the volume and surface area of a triangular prism. See how to easily find the volume and surface area of a triangular prism using these instructions.See Transcript
Transcript:How to Find the Volume and Surface Area of a Triangular Prism
Hi, I am Eric Stone from South Burlington High School in South Burlington, Vermont, here for About.com. Today, I am going to teach you how to find the volume and surface area of an isoceles triangular prism.
Surface Area and Volume
Before we go anywhere, lets start talking about surface area and volume in general. The general rule is, if you want to find the volume of any three dimensional solid, the typical rule of thumb is that what you want to do is find the area of the base and multiply it by the length that it travels through in space. In this case, the area of the base is going to be a triangle, and the formula for the area of a triangle is one half base times height. In this case, the base is going to be the distance from here to here -- we will call that the width -- and the height will be the distance from here to here.
What we are going to do then is we are going to take the area of the base and we are going to multiply it by the length that we are going to travel that through space. So the total volume is going to be the area of the base times the length -- so it is going to be one half the width times the height times the length, which is from here to here.
Finding the Surface Area of a Triangular Prism
To find the surface area of an isoceles triangular prism it is the same general idea, but you just have to stop and think. You want to find the area of all of the sides. Once you look at that you start to see that each of these pieces is a geometric shape that you are familiar with.
Finding the Area of a Triangular Prism
We need to find the area of this triangle. We need to find the area of the same triangle on the other side. We need to find the area of this, which is just a rectangle and the area on the other side which is just another rectangle. So all told, we are going to have to find, for the area of the prism, the area of two triangles plus the area of this rectangle, this rectangle, and the one on the other side.
In this case, our rectangle has a width and it has a length, like so -- and we have three. Simplify that up a little bit and we end up with base times height plus three rectanlges.
And that is how you find the volume and surface area of an isoceles triangular prism. Thanks for watching! To learn more, visit us on the web at About.com.