independent is the y value or the value that changes at a steady rate no matter what, the dependent variable or x is the variable that is subject to change and is dependent on the y value to find a pattern
Variables are given a special name that only applies to experimental investigations. One is called the dependent variable and the other the independent variable. The independent variable is the variable the experimenter changes or controls and is assumed to have a direct effect on the dependent variable.
Look here in a square which is what I imagine that drawing is all the angles are 90 degrees. A rectangle would be knowing two angles is know all of them one way or another so fix your work and you should know the answer