Answer:
from the same end, the ratio is n : m
Explanation:
(Letter refer to the attached figure.)
The diagonals (AC, BD) of a trapezoid (ABCD) divide the figure into triangles. Those triangles having parallel bases are similar (ABP, CDP). A line through the common point of those triangles (P, the intersection point of the diagonals) will further divide those similar triangles into similar triangles.
The ratio of the base segments will be the same (AX:XB = CY:YD). Since one triangle is "upside down" with respect to the other one, if the segment lengths are considered from the same side of the trapezoid, they are in the ratio m:n (=AX:XB) on one base and n:m (=DY:YC) on the other base.