Question 15In the figure below, $ABEF$ is a rectangle, $AD \perp DE,$ $AF = 7,$ $AB = 1,$ and $AD = 5.$ What is the area of $\triangle ABC?$ $\dfrac{3}{8}$$\dfrac{4}{9}$$\dfrac{1}{8}\sqrt{13}$$\dfrac{7}{15}$$\dfrac{1}{8}\sqrt{15}$
