__The volume (V) of the balloon with radius (r) is:__

V = 4/3πr^3

__Differentiating with respect to t, we get:__

dV/dt = 4/3π * 3r^2 * dr/dt

dV/dt = 4πr^2 * dr/dt

The rate of change of the volume is:

dV/dt = 10cm^3s^−1

__So, we find dr/dt:__

dr/dt = 1/4πr^2 * dV/dt

dr/dt = 10/4πr^2

dr/dt = 5/2πr^2

Therefore, dr/dt(2cm) is:

dr/dt(2cm) = 5/2π(2)^2

dr/dt(2cm) = 5/2π4

dr/dt(2cm) =

**5π/8**