bagaimana caranya dan jawabannya

AC / EH = AB / EF
AC / 25 = 20 / 50
AC = 20/50 x 25
AC = 10 cm

HG / CG = EF / AB
HG / 12 = 50 / 20
HG = 50/20 x 12
HG = 30 cm

HC = HG - CG = 30cm - 12cm = 18cm