I know -angle means… angles (triangle = three angles), and -agon means side (pentagon = 5 sides). But why was it decided that the naming conventions would be different by having some shapes named after the amount of angles and others be named after the amount of sides?
Additional superfluous thoughts:
Since rectangles are not named after the amount of angles (rect- means 90°, which is why all squares are rectangles), are all 4-sided shapes like trapezoids without 90° angles quadragons or quadangles?
EDIT: changed the structure of a sentence