Hi, You have to find length of AB (See screen) AB - is the hypotenuse of a right triangle ABC. According to the Pythagorean theoremAB = \(\sqrt{BC^{2} + CA^{2}}\) BC = AD + EB = 1 + 5 =6 CA=ED = 4 AB = \(\sqrt{6^{2} + 4^{2}}\) = \(\sqrt{36+ 16}\) ≈ 7.2
