We can use the Pythagorean theorem to solve this. We can first draw two more lines to complete the triangle. We then have two more lines, one with a length of 5, and another with a length of 7. The Pythagorean theorem states that a^2 + b^2 = c^2. 7^2 is 49, and 5^2 is 25. Add those together and you get 74. We then square 74, and get 8.602, which we can round to 8.6. The length of segment AB is 8.6.
