Let me start with the second screenshot :-
To find the scale factor you have to enlarge/ dilate A to get B you have a given side so assume that all sides are dilated to the same extent
: . \(1 \frac{1}{2} / \frac{3}{4} = 2\)
Thus one can say m would be
\(\frac{1}{2} * 2 = 1\)
And N would be
\(\frac{5}{6} * 2 = \frac{10}{6}\)
