If the circumference of a round barn is 56 meters, what is the diameter of the barn to the nearest whole meter ? use 3.14 for pi

We just started the introduction into circles and i have no idea how to do this.

You deposit $5000 each year into an account earning 3% interest compounded annually. how much will you have in the account in 30 years?

Aroulette wheel has 38 slots in which the ball can land. two of the slots are green, 18 are red, and 18 are black. the ball is equally likely to land in any slot. the roulette wheel is going to be spun twice, and the outcomes of the two spins are independent.the probability that it lands one time on red and another time on black in any order is(a) 0.5 (b) 0.25 (c) 0.4488 (d) 0.2244