what is the formular to work out the surface area of a prism?

Question

the prism has a rectangular base 36mm by 18mm. the height of the prism is 72mm tall.

Answer 1

Assuming a rectangular prism. You have 2 x ends, front and back, top and bottom.
ends = 2(18 x 72)
Front and back = 2(18 x 36)
top and bottom = 2(36 x 72)

Sum : ends + front and back + top and bottom to get total surface ared, Do the arithmatic your self.

Answer 2

The surface are would be the area of the base plus the area of the 4 sides:

Area (base) = 36 mm x 18 mm = 648 mm^2

Now the sides are a little trickier. is 72mm the height of the prism or the height of any one side of the prism? If it's the latter, then the calculation is easy:

Area (side) = 1/2 bh = 1/2 * 36 * 72 = 1,296 mm^2 -- this is for the side on the 36 mm side, and recall you have 2 of these

Area (side) = 1/2 bh = 1/2 * 18 * 72 = 648 mm^2 -- this is for the side on the 18 mm side, and recall you have 2 of these

So your total surface area would be 648 + 1296*2 + 648*2 = 3,240 mm^2

Now, if the 72 mm is the distance from the middle of the base of the pyramid to the top of the pyramid, you need to do some more math to figure out the height of the triangle that composes the sides of the pyramid.

Answer 3

The surface area of a prism = 2 × area of base + perimeter of base × H

now, area of rectangular base = length*width=36*18mm^2
and perimeter of rectangular base = (length+base)*2=(36+18)*2
and H=height of prism = 72mm

= 2 * (36*18) + (36+18)*2*72
=1296 + 7776
=9072mm^2

Answer 4

Find Surface Area And Volume of Prisms
http://www.ecsu.ctstateu.edu/depts/edu/units/surfacearea.html

Volume and Surface Area of Prisms
http://www.algebralab.org/Word/Word.aspx?file=Geometry_SurfaceAreaVolumePrisms.xml

Prism (geometry)
http://en.wikipedia.org/wiki/Prism_%28geometry%29
hope this helps :)

Answer 5

3 sides + 2 ends:
3 x (w x l) + (w x h)

where w and l are width and length of a flat side and h is the vertical height.

Answer 6

9072mm^2