Final answer:
To find OB', which is the length of the segment after dilation, multiply the original length by the scale factor. OB', the length after dilation, is 3 units.
Step-by-step explanation:
The question involves the concept of dilation in geometry. In this particular problem, we are given that Triangle ABC is dilated with a center of dilation at point O and a scale factor of 4 to produce Triangle A'B'C'. The original length of segment OB is 3/4 units. To find OB', which is the length of the segment after dilation, we simply multiply the original length by the scale factor, that is, 3/4 units × 4 = 3 units. Therefore, OB' is 3 units long after the dilation.