A paint tin is leaking, a circular puddle is formed and the radius of the
circle increases at a constant rate.
a) If the circumference of the circle
is increasing at a rate of 12cm/s, find
the rate at which the radius is increasing.

The rate at which the radius is increasing

dr/dt = 1.91 cm/s

Step-by-step explanation:

The circumference C of a circle can be written as;

C = 2πr 1

Where;

r = radius

The rate at which the circumference of the circle

is increasing can be written as dC/dt;

Differentiating equation 1, we have;

dC/dt = 2π dr/dt

Making dr/dt the subject of formula;

dr/dt = (dC/dt)/2π

Given;

dC/dt = 12cm/s

Substituting the value of dC/dt;

dr/dt = 12/2π

dr/dt = 1.909859317102 = 1.91 cm/s

The rate at which the radius is increasing dr/dt is 1.91 cm/s

answer: the correct one is a

step-by-step explanation:

8 2/3 is the answer

step-by-step explanation: just use a calculator