Respuesta :

Let the total number of cans be x and the total number of tennis balls be y,

Since increasing the total number of cans causes the total number of tennis balls to increase too, x and y is direct in proportion.

Let the constant be k,
y = kx
45 = k9
k = 45/9
= 5

The constant of the proportionality for this situation is 5.
RELAXING NOICE
Relax