Final answer:
A proportion to find out how much a piano tuner charges for 4 hours of work is ($63 / 1.5 hours) = (x / 4 hours). By solving this proportion, we find that the piano tuner would charge $168 for 4 hours.
Step-by-step explanation:
To find x, the number of dollars the piano tuner charges for 4 hours of work, we want to set up a proportion that compares the number of hours worked to the amount charged. Since the piano tuner charges $63 for 1.5 hours, we can use the ratio $63/1.5 hours to find out how much is charged per hour. Then, we can set up the proportion as follows:
($63 / 1.5 hours) = (x / 4 hours)
To solve for x, you would cross multiply and divide:
1.5x = 63 * 4
x = (63 * 4) / 1.5
x = 168
So the piano tuner would charge $168 for 4 hours of work.