Constructing Perpendicular Bisector of the given Line Segment

Using ruler and compasses, draw $AB=6.4 \mathrm{cm}$. Locate its midpoint by geometric construction. 

Ravi made a line segment of length $8.6 \mathrm{cm}$. He constructed a bisector of $AB$on $C$. Find the length of $AC \text{and} BC$.

Draw a line segment $PQ=5.8 \mathrm{cm}$ and construct its perpendicular bisector using ruler and compass.