Answer:
B'C' = 3BC
Explanations:
Note:
When a figure is dilated by a scale factor, a similar figure of the same shape but of different size is formed.
When a triangle ABC is dilated by a scale factor of 3, the vertices of the image of ΔA'B'C' formed will have a distance from the center of dilation that is three times that of the vertices of ΔABC
Therfore:
A'B' = 3AB
B'C' = 3BC
A'C' = 3AC
The correct choice is option B
That is, B'C' = 3BC