# volume cone hw ?

• Jan 29th 2010, 10:35 AM
igottaquestion
volume cone hw ?
A construction company wants to know how much sand is in a pile. The company measures that the distance from the edge of the pile at ground level to the very top of the pile is 55 ft. The company also measures that the distance around the pile at ground level is 220 ft.

a.) How much sand is in the pile?

b.) The construction company has trucks that carry 10 cubic yards in each load. How many loads will it take to move the pile of sand? Explain

for a i came up with 54454.2 cubic feet and then for b i got 202 truck loads. I am not sure if they are right, but can someone please try this and give me some feedback??? Is one cubic yard equal to 27 cubic feet?
• Jan 29th 2010, 10:41 AM
VonNemo19
Quote:

Originally Posted by igottaquestion
A construction company wants to know how much sand is in a pile. The company measures that the distance from the edge of the pile at ground level to the very top of the pile is 55 ft. The company also measures that the distance around the pile at ground level is 220 ft.

a.) How much sand is in the pile?

b.) The construction company has trucks that carry 10 cubic yards in each load. How many loads will it take to move the pile of sand? Explain

for a i came up with 54454.2 cubic feet and then for b i got 202 truck loads. I am not sure if they are right, but can someone please try this and give me some feedback??? Is one cubic yard equal to 27 cubic feet?

Recall: $C=2\pi{r}$

You were given $C=220ft$, so find $r$.

Also note that $r$ and $55ft$ respectively form the leg and the hypotenuse of a right triangle so that the hieght $h$ of the pile can be found by

$(55)^2-r^2=h^2$.

The Volume of the pile: $V=\frac{1}{3}\pi{r}^3$
• Jan 29th 2010, 10:52 AM
igottaquestion
i got r=110/pie

i thought the volume of a cone is 1/3 pie r squared h???
is this not right?

what did you get for the volume of the pile...i got 54454.2 cubic feet
• Jan 29th 2010, 10:55 AM
VonNemo19
Quote:

Originally Posted by igottaquestion

i thought the volume of a cone is 1/3 pie r squared h???
is this not right?

All I can say to that is......oops. You are correct. $V=\frac{1}{3}\pi{r^2h}$. Sorry about that.
• Jan 29th 2010, 10:57 AM
igottaquestion
have you looked at part b?
• Jan 29th 2010, 11:00 AM
VonNemo19
Quote:

Originally Posted by igottaquestion
have you looked at part b?

You mean $V/10$? I gave it a thought. (Wink) Oh, but dont forget to convert.