Answer :
let's pythagorean theorem!
a^2 + b^2 = c^2
a and b are the sides, c is the diagonal
3^2 + 5^2 = c^2
9 + 25 = c^2
34 = c^2
5.83 = c
a^2 + b^2 = c^2
a and b are the sides, c is the diagonal
3^2 + 5^2 = c^2
9 + 25 = c^2
34 = c^2
5.83 = c