realted rate cone chute problem

[markraz]

Hi, I have this related rate problem my teacher did in class. I'm sort of confused.
I have the answer as shown, but he blew through it real fast and my notes don't make sense.
At one point, he used a formula of v=2/3pi r^2 instead of v=1/3 pi^2h which I thought he would use??

any ideas?

thanks in advance

 

[stapel]

Hi, I have this related rate problem my teacher did in class. I'm sort of confused.
I have the answer as shown, but he blew through it real fast and my notes don't make sense.
At one point, he used a formula of v=2/3pi r^2 instead of v=1/3 pi^2h which I thought he would use??

It "blowing through it really fast", I'm guessing he skipped some steps, too. If you use the substitution, which is particular this this one exercise, of "2h" for "r", what do you get for the volume? (Plus, I'll bet the r was cubed.)