Why does one of the ratios in a percent proportion always have a denominator of 100?

Triangle xyz, with vertices x(-2, 0), y(-2, -1), and z(-5, -2), undergoes a transformation to form triangle x′y′z′, with vertices x′(4, -2), y′(4, -3), and z′(1, -4). the type of transformation that triangle xyz undergoes is a . triangle x′y′z′ then undergoes a transformation to form triangle x′y′z′, with vertices x″(4, 2), y″(4, 3), and z″(1, 4). the type of transformation that triangle x′y′z′ undergoes is a .