4.
The formula for the diagonal of a rectangle is:

Plug in what we know:

Simplify the exponents:

Add:

Take the square root:

For the second one, we know that the area of a square is:

Plug in what we know:

Take the square root of both sides:

So we know that the length and width are both 5 meters long, let's plug this into the formula for the diagonal:

Simplify the exponents:

Add:

Take the square root:
