q = y4/y3 = 2,25 : 3 = 9/4 : 3 = 9/4 * 1/3 = 3/4
y5 = y4 * q = 2,25 * 3/4 = 9/4 * 3/4 = 27/16
y2 = y3 / q = 3 : 3/4 = 3 * 4/3 = 4