1) 1/2:3/4 2) 2/3:1/3 3) 1/4:3/8
1/2 : 3/4 = 1/2 * 4/3 = 2/3, 2/3 : 1/3 = 2/3 * 3 = 2, 1/4 : 3/8 = 1/4 * 8/3 = 2/3