Problem One
The volume of a cone is
V= 1/3 * pi * r^2 * h
h = 20 so
V = 1/3 * pi * r^2 * 20 Multiply by 3
3V = pi * r^2 * 20 Divide by 20*pi
3V/(20*pi) = r^2 Take the square root of both sides.
√(3V/(20*pi) ) = √r^2 Switch
√r^2 = √(3V/(20*pi) )
r = √(3V/(20*pi) )
A is wrong because it is taking the cube root to find r. Only the square root is needed.
C is wrong because the right side is a square root, not squared.
D is wrong because it is the reciprocal (up side down) of the answer.
The answer is B.
Problem Two
Before you do anything else, find out what she charges for 1 dog.
27 dogs = 324
1 dog = x Cross multiply
27x = 324 Divide by 27
x = 324 / 27 Do the division
x = 12 dollars for 1 dog.
Now you can look at the graph. Plot the following points (x < 16)
Number dogs Amount
1 12
3 36
5 60
That's enough to get the line which I've given you below.
