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

b

step-by-step explanation:

the total is 23.97. 0.25% is off so you have to subtracting 25% from 100% and you will get 75% if you convert it to decimal you will get 0.75. you have to find the original because the formula is % times original = total.so you have the total and the % so you just have to plug it in.

i belive those are the ones that are under 90 degreese.