Answer: 24 units
Explanation:
If you are multiplying a shape by a scale factor, the dimensions are also multiplied by the scale factor.
QR= x
Q'R'= (1/2)(X)
12=(1/2)(X)
(2)12= 1/2x(2)
24=X
If you're multiplying QR by 1/2 you would get 12. 12 is a half of QR. Therefore, QR is 24.