A straight line is equal to 180. The line AB is 180 degrees. This means 174 + angle = 180 for the angle between point D and B. It must be 6 degrees. This is the same angle as the angle between point A and C.
Line CD is also straight and equal to 180. On the line are the angles, 4k + 90 + 3k + 6 = 180. Solve for k by combining like terms and then using inverse oeprations.
