Find the circumference of a circle with an area of 16mm

And explain how you got it so i can understand future problems : 3

Choosing a booth location: your manager is sending two people to work at the conference. she wants a booth that will give your company good visibility for no more than 35% of the total budget ($3000). the conference coordinator just told you there are only five booths left. which booth will you choose? write the inequality that shows how much money you can spend on the booth simplify the inequality that shows how much money you can spend on the booth.

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?