Me i'm desperate!

solve v=(1/3)(pi)h^2(3r-h) for r.

(if you want to see the question better, look at the picture)

also, explain how to solve it. (and if you could provide a visual, that would be great.)

The dolphins at the webster are fed 1/2 of a bucket of fish each day the sea otters are fed 1/2 as much fish as the dolphins how many buckets of fish are the sea fed each day? simplify you answer and write it as a proper fraction or as a whole or mixed number

Aculture started with 3000 bacteria. after 5 hours it grew to 3900 bacteria. predict how many bacteria will be present after 9 hours

Find the value of x. give reasons to justify your solutions! l, m ∈ kn