# Can someone help with volume and surface areas?

• Feb 7th 2010, 09:32 AM
DexterDawg
Can someone help with volume and surface areas?
Hi,
I'm new here and am looking for some help.
I'm trying to find the volume and surface area of a triangular prism.
The triangle is 1.25m wide and 1.7m high
The rectangle is 2m wide and 1.81 m high.
Does anyone know the formulas I have to use?
I have the answer here, I'm just not sure how to do the working.(Worried)

Thanks.
• Feb 7th 2010, 09:35 AM
e^(i*pi)
Quote:

Originally Posted by DexterDawg
Hi,
I'm new here and am looking for some help.
I'm trying to find the volume and surface area of a triangular prism.
The triangle is 1.25m wide and 1.7m high
The rectangle is 2m wide and 1.81 m high.
Does anyone know the formulas I have to use?
I have the answer here, I'm just not sure how to do the working.(Worried)

Thanks.

The triangle and a rectangle? I don't get what you mean.

A prism is defined as having the same cross sectional area along it's entire length.

In general: $\displaystyle V = A_{c}l$ where $\displaystyle A_c$ is cross sectional area and l is length

For a triangular prism $\displaystyle A_c = \frac{1}{2}bh$

$\displaystyle V_{\text{ triangular prism}} = \frac{1}{2}bhl$
• Feb 7th 2010, 09:50 AM
DexterDawg
I don 't get what I mean either....
The answers are in the back of my book and the volume should be 2.125m3 and the surface area is 9.37m2.
If anyone can work this out, please let me know what I'm talking about (Wink)