plese besok dikumpulin!

1).
= Np/Ns = Vp/Vs
= Np/60 = 12/4,5
= 4,5 Np = 720
= Np = 72/45
= Np = 160 Lilitan
......
2). 
= Np/Ns = Vp/Vs
= 100/Ns = 4/30
= 3000 = 4 Ns
= Ns = 3000/4
= Ns = 750 Lilitan
.......
3). 
= Np/Ns = Vp/Vs
= 20/100 = 25/Vs
= 20 Vs = 2500
= Vs = 2500/20
= Vs = 125 V
........
4). 
= Np/Ns = Is/Ip
= 20/25 = 3A/Ip
= 20 Ip = 75
= Ip = 75/20
= Ip = 3,75 A

Semoga membantu...... 
Centang yang terbaik ya :) :)