Two legs of a right triangle each measure 10 incles how long is the hypotenuse

The hypotenuse is:
  c = 10 * root (2) inches
steps:
first you have to apply the pythagorean theorem:
first c = root ((a) ^ 2 + (b) ^ 2)
  where,
  a, b: sides of the triangle
  c: hypotenuse
  substituting values we have:
  c = root ((10) ^ 2 + (10) ^ 2)
  c = root (100 + 100)
  c = root (200)
  c = root (2 * 100)
  c = 10 * root (2)

The second and fourth answer are correct