What is the length of a diagonal of a cube with a side length of 10 cm? 200cm, 210cm, 300cm, 320cm

IF the side length is 10cm, then the length of diagonal of the base of the cube (x) is X² = (10) ² + (10) ² = 200cm so x = 10√2cm

so the length of diagonal of the cube (y) is

y² = (10) ² + (10√2) ² = 300 so y = 10√3cm

None of these.

They are the possible squares of the diagonal