Since the given hypotenuse is 6.5 and one of the lengths is given as 6, we can use the equation a^2 +b^2 =c^2 to solve this. Plugging the numbers in, it would now be 6^2+b^2 =6.5^2, which would give you 36+b^2=42.25. Now, all you need to do is solve. Subtract 36 from 42.25, which will result in 6.25. Now, the equation is at b^2=6.25. All you need to do now is find the square root of 6.25, which would be 2.5, therefore giving you your answer.
