Hi

Question

Drawing a diagram will help:

A ladder 5m long leans against a wall, with the top of the ladder (B) reaching 4m up the wall and the foot of the ladder (A) is 3m from the wall (C). A man is at a point D which is 2m up the ladder.Point E lies on line AC and Point F lies on line BC. i.e. EDFC makes a square.

How can I prove that Triangle ADE is similar to triangle DBF?

Also, how can I find DE length and DF length?
Please provide working, too! Thanks so much!