If you look at triangle ADE, you can see that angles AED and DAE have been given to you. Since only one angle in that triangle is missing, and the sum of all of the angles in a triangle is always 180, you can add angles AED and DAE together and then subtract that from 180. 44+48= 92, 180-92=88. Angle ADE= 88. Perpendicular lines make 90 degree angles, and since angle ADE= 88 which is not 90 degrees, AC is not perpendicular to EF.