A triangle has two sides of lengths 7 and 12. What value could the length of the third dive be check all that apply

How to do this , and can some one explain

The complement of an angle is one-sixth the measure of the supplement of the angle. what is the measure of the complement angle?

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.