Thanks for writing in,
As per standard height weight chart of girls height of your younger girl is quite normal.
At this age a girl should have 118.2 cms height and about 19.4 kg weight.
This is the age when a child has maximum growth of height is there.
So nothing to worry.
Give her high protein nourishing diet like milk,cereals,pulses,cheese.panier etc.
Ask her to go for exercise like jogging,jumping ropes,cycling,swimming.
You may give calcium and multivitamin
Ok and bye.