Question

Triangle ABC is transformed with the center of dilation at the origin.

Pre-image: △ABC with vertices A(−5, −4), B(−7, 3), C(3, −2)

Image: △A′B′C′ with vertices A′(−3.75, −3), B′(−5.25, 2.25), C′(2.25, −1.5)



What is the scale factor of the dilation that maps the pre-image to the image?

Answer 1

Using the x coordinate  of  A'  and A   we have...

-3.75 / - 5    =    3.75 / 5  =    [ 3 * 1.25 ]  / [ 4 * 1.25 ]   =    3/4  =  scale factor