20. Five marks exercise problem VII

In $\Delta ABC$, with $\angle B = 90^\circ$, $BC = 6 \ cm$ and $AB = 8 \ cm$, $D$ is a point on $AC$ such that $AD = 2 \ cm$ and $E$ is the midpoint of $AB$. Join $D$ to $E$ and extend it to meet at $F$. Find $BF$.

 

Answer:

 

The value of $BF$ $=$  $cm$