Posted by **noor** on Monday, April 27, 2009 at 10:00am.

hey i need to understand how to figure out an area of a 3-D prizm. sreached on the web but dont understand it please help

- math -
**Reiny**, Monday, April 27, 2009 at 10:47am
by "area of a 3D prism" , do you mean the surface area of the shape, or did you mean volume ?

Either way, you will have to be much more specific as to the kind of prism you are referring to.

In general, the surface area would be the total of the areas of all the faces.

in general the volume is (the area of the base)x(the height).

- math -
**Dr Russ**, Monday, April 27, 2009 at 10:52am
There are a number of prism shapes. In all cases the surface area of a prism is the area of the ends plus the area of the sides.

Lets look at a regular triangle prism (i.e. a toblerone shape) with sides a and length l. The ends are equilitaeral triangles so the area is

a^2root3/4

(area of triangle is 0.5xbasexheight, height of equlateral triangle is axroot3/2 so area is a/2 x a x root3/2)

The three sides of the prism are all rectangles, area=al

so the surface area of the prism is

2(a^2root3/4)+3al

But check my maths!

You can do the same for each shape of prism.

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