вычислите пожалуйста!!!!!!!!

1)      ..........=(5/12) / (5/9)=5/12 * 9/5=3/4

2)   .....=(1/4) / (1/2)=1/4 * 2/1=1/2

3)   ......=(7/15*15/4) / (21/8)=7/4 * 8/21=2/3

4)    .........=(1/3) / (2/9)=1/3 * 9/2=3/2=1 1/2