The table shows how much jake charged for the last 4 orders of pup cakes. what is the constant of proportionality in cost per pup cake?

$2.50

Step-by-step explanation:

Let's take a look at the 4 orders and check the price per pup cake in each order:

Order 1: $5 for 2 cakes, so $2.50 per cake.

Order 2: $7.50 for 3 cakes, so $2.50 per cake.

Order 3: $12.50 for 5 cakes, so $2.50 per cake.

Order 4: $20.00 for 8 cakes, so $2.50 per cake.

Jake has a very consistent pricing of his cakes... they're always $2.50 each.

That price is the relation between the price asked and the number of cakes sold, that's the constant of proportionality in this case.