Part A: Let the September price be x, then
1.2x = 1.5
x = 1.5/1.2 = 1.25
Therefore, September price is $1.25
Part B: In September, they earned 0.4 * 1.25 * 900 = $450
In October, they earned 0.4 * 1.5 * 700 = $420
Therefore, they earned more money in September.
Answer:
The relationship between the circumference of a circle and its diameter represent a direct variation and the constant of proportionality is equal to the constant 
Step-by-step explanation:
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form 
where K is the constant of proportionality
In this problem we know that
The circumference of a circle is equal to

therefore
the relationship between the circumference of a circle and its diameter is a direct variation and the constant of proportionality is equal to the constant 
Square root of 15 because you don't know what know is going to go after it, unlike the others where you can guess the numbers that goes after it
First 6, then 11, then 13.5, then (honestly I don't know the rest). '__'