Why is number multiplied by it self called a square of a number

I'm being volume of cylinder with 13 in. radius and 30 in height answer choices in pic

X-10/4 when x = –18 a 7 b –2 c –7 d 2

The bottom of ignacio's desktop is 74.5cm from the floor. ignacios sits in his adjustable chair, and the tops of his legs are 49.3cm from the floor. each clockwise rotation of the knob on the chair raises ignacio's legs by 4.8cm. write an inequality to determine the number of clockwise rotations, r, ignacio could make with the knob without his legs touching the desk.