The coordinates of △ABC are A(12,8), B(10,18), C(4,16) . After a dilation, the coordinates are A'(6,4), B'(5,9), C'(2,8) A′(6,4), B′(5,9), C′(2,8) . Find the scale factor.
Let's look at A and A'. This is (12,8) and (6,4). As you can see, each value in A' is 1/2 of that in A. In all the other points, their dilated point is 1/2 the original.