Does a machine that takes one quarter at a time into its input and produces two gumballs in its output act like a function?

Yes, because for a function the output should always be the same for the same input.

So when you input 1 quarter you always get 2 gumballs. ( the number of gumballs is always 2 and doesn't change).

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6

$25

step-by-step explanation:

25 - 4.50 = 20.5

20.5 / 2 = 10.25

10.25 + 10 = 20.25

20.25 - 12.50 = 7.75

therefore the answer is $25 as shown as the first number.