Answer:
The scale factor is 1/2 or .5
Explanation:
Triangle XYZ scales down by 1/2 to form the new XYZ triangle
For example: on the left side, X is (6,4) and on the right side, X is (3,2)... it's cut in half meaning the scale factor is 1/2 or .5
Hopefully this isn't confusing and it helps... :)