Prove whether or not the triangles ADE and FBE are similar. What parts are corresponding?

In this diagram there are three pairs of similar triangles name at least one of them and prove that they are similar.

If CD is 21 units long, AB is 7 units long, and DE is [math]12\sqrt{2}[/math] units long, how long is AE?

It's time to replace the large canvas on your boat (the main sail). You replaced the smaller sail (the Jib sail) last year. You got the angle measurements shown above. You also know that the bottom edge of the main sail is 12 feet long and the bottom edge of the jib sail is 6 feet long. Any other measurements would be significantly harder to take, but you're in luck because Mr. Rose's Geometry class gave you the skills to forego those measurements with the information you have. Sail canvas is sold by the square yard and you remember that the jib was 3 square yards. Right now Canvas is about $23 per square yard. How much is the new sail going to cost?