Question

The volume of a cantaloupe is approximated by Upper V equals four thirds pi font size decreased by 5 r cubed . The radius is growing at the rate of 0.5 cm divided by week​, at a time when the radius is 6.4 cm. How fast is the volume changing at that​ moment?

Answer 1

308.67 cm ^ 3 / week

Explanation:

A cantaloupe is approximately a sphere, therefore its approximate volume would be:

V = (4/3) * pi * (r ^ 3)

They tell us that dr / dt 0.5 cm / week and the radius is 6.4 cm

if we derive the formula from the volume we are left with:

dV / dt = (4/3) * pi * d / dr [(r ^ 3)]

dV / dt = (4/3) * pi * 3 * (r ^ 2) * dr / dt

dV / dt = 4 * pi * (r ^ 2) * dr / dt

we replace all the values and we are left with:

dV / dt = 4 * 3.14 * (6.4 ^ 2) * 0.6

dV / dt = 308.67

Therefore the volume is changing at a rate of 308.67 cm ^ 3 / week