In a rhombus each diagonal bisects the other to form 4 right triangles. The side lengths of these triangles will be half the diagonal lengths since the diagonals were bisected. This leaves us triangles with side lengths of 20 and 48 with the hypotenuse being a side length of the rhombus. Apply the pythagorean theorem:
Think of there being 8 different places that you can put a single piece of fruit. when you first start pick a spot, there are 8 different options you have for putting a piece there. Once you place it you move to the second spot, you now have seven pieces of fruit left to pick from because one was already used. Go to the third spot, now you only have 6 pieces to pick from. This continues until you run out of fruit and places to put it.
My response will be based on the assumption that you mean triangle QWE rather than DeltaQWE and also that we are working in a plane.
Since the interior angles sum to 180, that means angle W=45 and we have an isosceles right triangle. With that, knowing one leg, EW=7, guarantees the other leg is congruent so WE=7 as well.
In a 45-45-90 triangle the hypotenuse is always longer than the legs by a factor of sqrt(2), ergo QW=7sqrt(2)