Could someone walk me through these problems, step by step?

1. Use figure 1 below. A ring of grass with an area of 314 yd^2 surrounds a circular flower bed. Find the width x of the ring of grass.

2. Use figure 2 below. Bob cuts four congruent squares from the corners of a 30 in. by 50 in. rectangular piece of cardboard so that it can be folded to make a box. Find the side length s of the squares, given that the area of the bottom of the box is 200 in^2.

3. Use figure 3 below. Billy has 80 m of fencing materials to enclose three sides of a rectangular garden. She will use the side of her garage as a border for the fourth side. Find the width x of the garden if its area is too be 700 m^2.

If anyone could help me out, that would be great!