An atom with 16 electrons must have how many shells? 

Use circumcenter theorem to solve for the given values

Timmy uses 1 1 2 cups of sugar for every 2 gallons of lemonade he makes. how many cups of sugar would timmy use if he makes 13 gallons of lemonade?

Consider circle c with angle acb measuring 3/4 radians. if minor arc ab measures 9 inches, what is the length of the radius of circle c? if necessary, round your answer to the nearest inch.