## 2 word problems. Thanks for any and all help.

Geometric formulae, word problems, theorems and proofs, etc.
kyl367
Posts: 6
Joined: Thu Feb 18, 2010 2:12 am
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### 2 word problems. Thanks for any and all help.

1. How many cubic yards of concrete are needed to pour a concrete slab 24 feet long, 14 feet wide, and 8 inches thick?
V=Ah
A=LW
A=24 * 14= 336 ft^2
V= 336 * h
V= 336ft^2 * .67 ft =225.12 ft^3
225.12 cubic feet divided by 27= 8.34 cubic yards
2. How many cubic feet of concrete are needed to pour 4 cylindrical pillars 6 feet high with a diameter of 10 inches?
(pi) (r^2) (h)
3.14 X 25 X 72 in =5652 in^2
5652 X 4=22608 in^2
22608 / 1728= 13.08 cubic feet

maggiemagnet
Posts: 358
Joined: Mon Dec 08, 2008 12:32 am
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### Re: 2 word problems. Thanks for any and all help.

1) Something went wrong with your conversion. Instead of doing the conversion at the end, try working with the fractions at the beginning: (24/3)*(14/3)*(8/3). That way, your answer will already be in "cubic yards".

2) How did you get that 10/12 feet, when squared, equalled 25...?