Call the new points under dilation A', B'.......they are given by:
A' = [2*3.5, 2*3.5] = [7, 7] and B' = [ 3*3.5, 8*3.5] = [ 10.5, 28 ]
The slope = [28 - 7] / [ 10.5 - 7] = 21/ 2.5 = 210/25 = 42/5
The length of A' B' = sqrt [ (10.5 - 7)^2 + (28 - 7)^2 ] = sqrt [ 3.5^2 + 21^2] =
sqrt [ 12.25 + 441] = sqrt [ 453.25] = about 21.29 units
