Tuesday, April 18, 2006

Volume and Surface area quetions

1. How much cement is needed to build a sidewalk that is one thousand, one hundred twenty metres long, four metres wide and fifty centimetres thick? Round your answer to the nearest cubic metre.

1120 x 4 x .5 = 2240m3
2240m3 is the amount of cement you need.

But if you're finding surface area, here's how to do it.
1120 x 4 = 4480m x 2 = 8960m
1120 x .5 = 560 x 2 = 1120m
.5 x 4 = 1m x 2 = 2m

8960 + 1120 + 2 = 10082m2

right? =/

3. If you have five 5 cm by 5 cm x 5 cm aluminum cubes and superglue them together in a row, what is the surface area of the resulting shape made by the five cubes?

First you have to put the five cubes together. So that means that you'll have one long rectangle. The base will be 5cm long. The height will be 25cm long and the width will be 5 cm long.

5 x 5 = 25 x 2 = 50cm
25 x 5 = 125 x 2 = 250cm
25 x 5 = 125 x 2 = 250cm
50 + 250 +250 = 550cm2

So the total surface area is 550 cm2

annalynaniciete ; nannalyn




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