Question

Segment CD is given with vertices C(a,b) and D(2a,b). Find the length of segment C'D', the image of segment CD after a dilation with a scale factor of 2.

Answer 1

the dilation is a scale factor of 2, that is:

C'D' = 2(CD)

the length of CD is given by:
CD = √( (a - 2a)^2 + (b - b)^2 )

CD = √(a^2) = a

hence the new segment is 2a long.