Answer: The scale factor is 2/5 and the length of BC is 10
Given: We have to find the factor of dilatation by looking at the pre-image ABCD and the image A'B'C'D' and then we have to find the length of the segment BC.
Step-by-step explanation: To calculate the dilatation factor we have to look at two given segments, the side D'C' and the side DC since the segment DC belong to the pre-image and the segment D'C' belongs to the image we know that the factor of dilation will be the same for the change relation between those two sides and any other side of the figure so:
Scale factor = 2/5
Now in order to find the measure of the side BC we have to multiply 4 by the inverse scale factor because we are going from the image to the pre-image so:
Length of BC = 4 * 5/2 = 10