Guys i need help how do i find the circumference of a circle?

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?

Zoey made 5 1/2 cups of trail mix for a camping trip. she wants to divide the trail mix into 3/4 cup servings. a. ten people are going on the trip. can zoey make enough 3/4 cup servings so that each person gets one serving? b. what size would the servings need to be for everyone to have a serving?

It is saturday morning and jeremy has discovered he has a leak coming from the water heater in his attic. since plumbers charge extra to come out on the weekends, jeremy is planning to use buckets to catch the dripping water. he places a bucket under the drip and steps outside to walk the dog. in half an hour the bucket is 1/5 of the way full. what is the rate at which the water is leaking per hour?