Suppose A is directly proportional to the square of B,and A=45 when B=3.

a)Find the constant of proportionality
b)Write the formula for A in terms of B
c)Use your formula to find A when B=6

2 answers

A = k B^2

a) 45 = k * 3^2 ... k = ?

b) A = ? B^2

c) A = ? * 6^2
Given
A=45 , B = 3
A∝B^2
That means A= k B^2
Where k is proportionality sign
a) 45 = 9 k
k = 5 ( constant of proportionality)

b) A = 5 B^2

c) when B =6 A=?
A = 36×5
A= 180
I hope it will help you.