tell whether the two rates form a proportion

1.) 75 miles in 3 hours; 140 miles in 4 hours
2.) 12 gallons in 4 minutes; 24 gallons in 7 minutes
3.) 150 steps in 50 feet; 72 steps in 24 feet
4.) 3 rotations in 675 days; 2 rotations in 730 days