+180 In triangle ABC, D,E and F are the midpoints of BC, CA and AB respectively. A dilation maps A to D, B to E and C to F What is the scale factor of this dilation?
+1768 The scale factor of a dilation is equal to the ratio of the length of the image of a segment to the length of the pre-image of that segment.
Since D is the midpoint of BC, the scale factor of the dilation is the ratio of the length of DE to the length of BC. Since the length of DE is half the length of BC, the scale factor of the dilation is 1/2.
