This segment creates a right triangle with the x and y axis. The two legs are 8 units and 6 units. Using the Pythagorean theorem, we know that 8^2+6^2=x^2, when x is the length of AB. 8^2+6^2=100. Therefore, 100=x^2 We can then take the square root of both sides to find that: x=10. Hope this is helpful!