What is an easy way to figure out what operation to use when solving problems. e. g how may 3/4 are there in 6

Acircular city park has a sidewalk directly through the middle that is 111 - feet long. if each bag of fertilizer covers 50 square feet, then determine how many bags of fertilizers the parks and recreation department needs to use to cover the circular park. ignore all the sidewalks around and through the park.

What is the length of the missing leg in this right triangle? 18 mm 24 mm 26 mm 32 mm

What is the order of magnitude for the number of liters in a large bottle of soda served at a party