to find the value of X in this example notice that we have a right triangle so we can use the Pythagorean theorem the Pythagorean theorem states that the sum of the squares of the lengths of the legs of a right triangle is equal to the square of the length of the hypotenuse or a squared plus B squared equals C squared where a and B are the lengths of the legs of the right triangle and C is the length of the hypotenuse so here since the legs of the right triangle have lengths 6 & 8 and the hypotenuse has a length of X we can set up the equation 6 squared plus 8 squared equals x squared simplifying from here 6 squared is 6 times 6 or 36 and 8 squared is 8 times 8 or 64 so we have 36 Plus 64 equals x squared next 36 plus 64 is 100 and we have 100 equals x squared now to get X by itself since X is squared we take the square root of both sides of the equation on the right the square root of x squared is X and on the left since 100 is the perfect square 10 times 10 the square root of 100 is 10 so 10 equals x notice that we don't use plus or minus 10 because X represents the length of the hypotenuse of the triangle which cannot be negative so the value of x is 10