The four points A(-4,0), B(0,-4), X(0,18) and Y(20,k) are grouped on the Cartesian plane. If segment AB is parallel to segment XY what is the value of k?
Parallel lines ( or their segments) have the same slope
So slope of AB = [ -4 - 0 ] / [ 0 - - 4 ] = -4 / 4 = -1
So ....using the same idea
[ k - 18 ] / [ 20 - 0 ] = -1
[ k - 18 ] / 20 = -1 multiply both sides by 20
k -18 = -20 add 18 to both sides
k = -2
