Math help! tires and revolutions.

Mercury mariner's tire diameter is 29 inches. Ford Taurus's tire diameter is 27.2 inches. How many more revolutions must the tire of the Ford Taurus make in order to travel a mile?

For Mercury Mariner's tire Circumference = pi x diameter = 3.1416 x 29inches = 91.10 inches

1 mile = 63,360 inches

Circumference of car wheel = 3.14159 x 29 inches
Number of revolutions made by the car wheel when
the car travels a distance of 1 mile = 695.50

For Ford = 3.1416 x 27.2 inches
Number of revolutions made by the car wheel when
the car travels a distance of 1 mile = 741.49

For needed answer ---- 741.49 - 695.50 = 45.99 inches needed.

A mile is 5280 feet X 12 = 63,360 inches
The circumference of the Mercury's tire is 29 X pi = 91.1 inches
The circumference of the Ford's tire is 27.2 X pi = 84.45 inches

So, the Mercury will need 63,360 divided by 91.1 = 695.5 revolutions to cover a mile.
And the Ford will need 63,360 divided by 84.45 = 750.27 revolutions

The difference is 750.27 - 695.5 = about 54.7 revolutions.

= - (12[5,280])/(22/7[29]) + (12[5,280])/(22/7[136/5])
= - (63,360/[638/7]) + (63,360/[2,992/35])
= - (63,360[7/638]) + (63,360[35/2,992])
= - 443,520/638 + 2,217,600/2,992
= (- 60,318,720 + 64,310,400)/86,768
= 3,991,680/86,768 or 46

Answer: 46 more revolutions

find the circumference, then work from there