Jawabanmu

2014-05-29T09:24:27+07:00
So = 4 m
= 400 cm
Si = -25 cm
1/fokus (1/f) = 1/400 - 1/25
= 1/400 - 16/400
= -15/400
f = -400/15
= - 26 10/15
= - 26 2/3 cm
2014-05-29T10:14:38+07:00
So = 4 m
= 400 cm
Si = -25 cm 
1/fokus (1/f) = 1/400 - 1/25
= 1/400 - 16/400
= -15/400
f = -400/15
= - 26 10/15
= - 26 2/3 cm