The lateral area of any right prism is the perimeter of the base times the height. If you remember it this way, it's much easier - it accounts for the base to be of any shape - rectangles, triangles, pentagons, and even circles (in which case you'd have a cylinder, which is essentially the same as a right prism).
In your problem, you have the length, width, and height:
L = 3
6W = 3
W = 1/2
5H = 3
H = 3/5
So we can find the lateral area first. The perimeter of the base is 3 + 1/2 + 3 + 1/2 = 7. The height is 3/5, so LA = 21/5.
The total area of any right prism is the lateral area plus twice the area of a base. Again, this works for any right prisms, including cylinders. In your problem, the area of the base is 3 * 1/2, or 3/2. You need two of these plus the LA, so the total area is then 21/5 + 2(3/5) = 36/5.
The volume of the prism is the area of the base times the height. The area of the base is 3/2 (we found that already), and the height is 3/5. So the volume is then 3/2* 3/5 = 9/10.
2007-04-27 15:26:06
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answer #1
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answered by igorotboy 7
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