One company, wants to package tennis balls in a triangular arrangement. The diameter of one tennis ball is about 6.75 cm. There are three tennis balls. How much empty space is in the tennis ball canister?

You coordinate volunteers for litter cleanup in local parks. your spreadsheet lists drivers and the number of seat belts in each driver’s car. the spreadsheet calculates the number of drivers (d) and the total number of seat belts (s). you want to know the maximum number of volunteers, besides drivers, that can be transported to the park in a single trip given that each person must have a seat belt of their own.