We want to draw a conclusion about the scale factor for the dilation shown by only watching the given graph, the only conclusion we can take is that a scale factor is a number between 0 and 1. So we have a transformation that transforms the triangle ABC into the triangle A'B'C'.You can see that it is a dilation about the black dot seen in the given image, if the scale factor was a number larger than 1, then the dilated points would be further away from the black dot. But that is not the case, we can see that the images of the dilation are closer to the black dot, then this is not a "real" dilation, this is actually a contraction (where a contraction is a "dilation" of scale factor between zero and 1). Then the only thing that we can conclude with the given image is that the scale factor of the dilation shown is a number larger than 0 and smaller than 1.
Easy! just compare then cross multiply 70:1 × 10:4 because you need to use the negative reciprocal of either one to create division with ratios/fractions
