Hey,
I could actually answer the question now, so I am going to put it here as well so the people don't have to read the comments above.
Use the Pythagorean Theorem to find the hypotenuse:a² + b² = c²
5² + 5² = c²
25 + 25 = c²
50 = c²
√50=√(c^2 )
7.07 = c
Answer: 7
Cheers,
Izzy