the coordinates of the vertices of triangle abc are a(9, –10), b(–15, 0), and c(15, 10). a dilation centered at (0, 0) is perfomed on triangle abc to produce triangle a'b'c'. the coordinates of the vertices of triangle a'b'c' are a'(13.5, –15), b'(–22.5, 0), and c'(22.5, 15). find the scale factor.