Okay, I am having some problems with my Maths homework. I know there is another Maths thread already doing the rounds in GC, but I just figured the probability of getting a quick response may be slightly higher if I created a separate thread, bla bla bla, you get the picture!

Here are the two offending questions:

1. The sides of a rectangle are in the ratio 2:3. The diagonal is of length 26cm. Find the perimeter.

2. A cube has volume 10cm^3. Find the sum of the lengths of the edges, and the total surface area.

Oh, by the way. I already have the answers to these questions, as they are written on the back of the sheet. However, I don't know how to work the answer out. So if anyone can explain how to work it out, I'd really appreciate it.