Making a table helps compare two or more sets of data because you can see how much it has increased or decreased.
Consider two triangles AEB and CEF. In these triangles:
- ∠AEB≅∠CEF (as vertical angles);
- ∠EAB≅∠ECF (lines AB and CD are parallel and AC is transversal, then these angles are congruent as alternate interior angles);
- ∠ABE≅∠CFE (lines AB and CD are parallel, BF is transversal, then these angles congruent as alternate interior angles).
Thus, by AAA theorem, 
Corresponding sides of similar triangles are proportional, then

ABCD is a parallelogram, then AB=CD.
Therefore,
CD=2CF and CD=DF+CF. Equate these two expressions:
DF+CF=2CF,
DF=CF.
This gives you that DF:CF=1:1.
Answer: 1:1
2010 47 +ten thousand split decide and
The triangle that is formed from by connecting the shadow, the tree and the endpoints of each is a right triangle. The two triangles formed (by the tree and its shadow, and by Rachel and her shadow) are similar. In similar triangles, the corresponding sides are proportional. Thus, to give the numerical answer to this item,
length of the tree/14 ft = 6 ft / 3.5 ft
length of the tree = 24 ft