What does it mean to square a number

How many sides does a regular polygon have if each exterior angle measures 72a.3b.4c.5d.6

An object is translated by (x + 4, y - 2). if one point in the image has the coordinates (5, -3), what would be the coordinates of its pre-image? (9, -5) (1, -5) (9, -1) (1, -1)

A25- foot ladder leans against a building and reaches a point of 23.5 feet above the ground .find the angle that the ladder makes with the building