Triangle DEF is similar to triangle ABC. Solve for y.
y =
D
37.5
20
B
27.5
16.5
Y
12
A

The volume of a spherical hot air balloon v(r) = 4 3 ? r3 changes as its radius changes. the radius is a function of time given by r(t) = 3t. find the instantaneous rate of change of the volume with respect to t at t = 2.