# Homework Help: Related Rates water level

1. Jan 31, 2012

### iRaid

1. The problem statement, all variables and given/known data
12.) A trough is 15ft long and 4ft across the top as shown in the figure. Its ends are isosceles triangles with height 3ft. Water runs into the trough at the rate of 2.5 ft3/min. How fast is the water level rising when it is 2 ft deep?

2. Relevant equations

3. The attempt at a solution

Not sure how to do this..
dv/dt = 2.5

I tried using the volume of a triangular prism: V=(1/2)bhl but no success.. I think the problem is IDK which numbers to use for the volume equation?
Can someone point me in the correct direction?

#### Attached Files:

• ###### d.jpg
File size:
15.6 KB
Views:
131
Last edited: Jan 31, 2012
2. Jan 31, 2012

### iRaid

Edit: Attached picture

3. Feb 1, 2012

### iRaid

If anyone is looking at this, what you have to do is find the area of the water, not the actual triangular prism.

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook