Final answer:
Side S'T' of the dilated quadrilateral QR'S'T' is 3/4 the length of the original side ST in quadrilateral QRST since the scale factor of the dilation is 3/4.
Step-by-step explanation:
The student is asking about the effect of a dilation with a scale factor on the side lengths of a quadrilateral. If quadrilateral QRST is dilated by a scale factor of 3/4 to form quadrilateral QR'S'T', this means that each side of the original quadrilateral is multiplied by 3/4 to get the corresponding side length in the new quadrilateral.
Therefore, for side ST of the original quadrilateral, its corresponding side in the new quadrilateral, S'T', will be 3/4 of the original length of ST. The correct answer to the question is A) 3/4 of the original length of ST.