Final answer:
The new line drawn through the center of a dilated rectangle coincides with the original line, preserving collinearity.
Step-by-step explanation:
The relationship between the new line drawn through the center of the dilated rectangle and the original line EF is that the new line will coincide with EF because the dilation preserves collinearity. When a geometric figure is dilated with any scale factor, the points that were collinear (lying on the same line) before the dilation remain collinear after the dilation. Since line EF was drawn through the center of rectangle ABCD, and rectangle ABCD was dilated with a scale factor of 3, the center of the dilated figure will still be on line EF. Therefore, a new line drawn through the center of the dilated figure will be the same line EF, just extended if needed to match the new dimensions.