So the ladder is 4 feet from the wall and 18 feet tall. This can translate to negative 4 spaces on the x-axis and 18 spaces on the y-axis. The slope of a line is rise over run which is 18/4 or 4.5
I hope the answer is right and I hope I helped. Have fun with the rest of your math :)
Each transversal crossing a line generates 2 pairs of vertical angles and for 3 transversal crossing the same line it will be 3 x2 = 6 pairs (or 12 angles)