mohon bantuan nya kawan

1.Dongkrak Hidrolik
dik:
diameter1=3mm
jari jari1=1,5mm=15/10.000m
diameter2=120mm
jari jari2=60mm=6/100m
F2=800N

dit:
F1=?

dijawab:
F1/A1=F2/A2
F1/15×15×3,14×10^-8=800/6×6×3,14×10^-4
3600F1=1800
F1=0,5N

2.Tekanan hidrostatis
dik:
massa jenis minyak=0,8g/cm3=800kg/m3
h=3/4×1=0,75m
g=10N/kg

dit:
Ph=?

dijawab:
Ph=massa jenis×h×g
Ph=800×0,75×10=6000N/m2