How would you get the answer of how much change he received

Step-by-step explanation:

Givens

I foot of sill = 1.75

35 feet of sill = x

Paid with 100 dollars.

Solution

First part

Solve the proportion

1/35 = 1.75/ x                 Cross multiply

1*x = 35 * 1.75

x = 61.25

Second part

Get the change.

Change = 100 - 61.25

Change  = 38.75

The change =

3 tens                30.00

1 five                   5.00

3 ones                3.00

3 quarters           .75

Total                 38.75