How do you figure out the balance of the retained earnings?

What is the square root of 45? (step by step working plz)

Apark is in the shape of a rectangle. the park authorities are planning to build a 2-meter-wide jogging path in the park (shown as the shaded region in the image). what is the area of the jogging path? plz

Kai walked one and two-thirds of a mile on saturday and four and one-sixth of a mile on sunday. how many miles did kai walk?