The volume of a right cylinder is 684t cubic inches and the height is 18 inches. find the radius.

Hurry if the population of of an ant hill doubles every 10 days and there are currently 100 ants living in the ant hill what will the ant population be in 20 days

X/y + 4y/x divided by x/y - 2y/x explain as in depth as you can how you simplfied the fractions. i don't know where to start on this : /

Acentral angle measuring 160 degrees intercepts an arc in a circle whose radius is 4. what is the length of the arc the circle formed by this central angle? round the length of the arc to the nearest hundredth of a unit. a) 4.19 units b) 6.28 units c) 12.57 units d) 12.57 square units