A triangle has a total angle of 180 degrees. Since we know that angle X = angle N = 20 degrees and angle Y = angle M = 75 degrees, therefore angle Z or angle L is equal to:
angle L = 180 – 20 – 75
angle L = 85 degrees
Therefore w is:
angle L = 5 (w – 2)
5 (w – 2) = 85
w – 2 = 17
w = 19