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
: . [tex]1 \frac{1}{2} / \frac{3}{4} = 2
[/tex]
Thus one can say m would be
[tex] \frac{1}{2} * 2 = 1[/tex]
And N would be
[tex] \frac{5}{6} * 2 = \frac{10}{6} [/tex]
