To solve you have to use Pythagorean Theorem: a^2+b^2 = c^2 You’re looking for b so the formula would be: b^2 = c^2-a^2 10.5^2-6^2 110.25-36 74.25 The square root for 74.25 is 8.61684396... But it tells you to the nearest tenth so the answer would be 8.6