How do I set this up to work it?

The length of a rectangle is 1 cm longer than its width. If the diagnol of the rectangle is 4cm, what are the dimensions of the rectangle?

Use Pythagoras

x^2 + (x+1)^2 = 16

Expand to get a quadratic equation. Solve using the formula and use only the positive answer

(I got a width of 2.28 and a length of 3.28)