Answer:
The circumference and diameter of a circle
Step-by-step explanation:
Proportional relationships can be written as [tex]y=kx[/tex], where [tex]k[/tex] is some constant of proportionality. The formula for a circumference of a circle can be written as [tex]C=d\pi[/tex], where [tex]d[/tex] is the diameter of the circle. Therefore, the constant of proportionality is [tex]\pi[/tex] and the circumference and diameter of a circle are in a proportional relationship.
