Answer:
ac will also be doubled.
Explanation:
We are given that the Point b is on line ac and lies between a and c.
ab is doubled
bc is also doubled
Now we have to predict the effect on ac.
Let ab= x
bc=y
ac=ab+BC
ac=x+y ----(A)
Now after increasing the length
AB =2x
BC=2y
AC=AB+BC
AC=2x+2y
AC=2(x+y)
AC=2ac (From eqn A)
Hence the length of ac will also be doubled up.