Tlg bntu ya kawand Thanks

f = 6 cm
So = 10 cm
ho = 4 cm

1/f = 1/So + 1/Si
1/6 = 1/10 + 1/Si
1/Si = 1/6 - 1/10
1/Si = 5/30 - 3/30 = 2/30
Si = 30/2 = 15 cm

M = Si/So = 15/10 = 1½
hi = M. ho = 1½ × 4 = 6 cm