Note: Consider we need to find the constant of proportionality.
Given:
The cost y (in dollars) to rent a kayak is proportional to the number x of hours that you rent the kayak.
It costs $27 to rent the kayak for 5 hours.
To find:
The constant of proportionality.
Solution:
The cost y (in dollars) to rent a kayak is proportional to the number x of hours that you rent the kayak.
[tex]y\propto x[/tex]
[tex]y=kx[/tex]
where, k is constant of proportionality.
It costs $27 to rent the kayak for 5 hours. So, put x=5 and y=27 in the above equation.
[tex]27=k(5)[/tex]
Divide both sides by 5.
[tex]\dfrac{27}{5}=k[/tex]
Therefore, the constant of proportionality is [tex]\dfrac{27}{5}[/tex].