Answer:
About 3.052 units
Explanation:
I presume you won't need this explanation now, but just in case;
If we draw triangle MNK, as MN = NK we know is isosceles. Now let's draw an altitude to MK so that it splits MK into two congruent parts (5/2 = 2.5). Given M<N = 110 degrees the altitude would split the angle into two congruent angles as well (Coincidence Theorem)---- 110/2 = 55 degrees.
Now let's study the smaller triangles, and take one as an example. Remember sin(theta) = opp/hyp. Applying this we have theta as 55 degrees, the opposite side as 2.5, and the hypotenuse is yet to be found (MN);
sin(55°)= 2.5/MN,
x = 2.5/sin(55°) ≈3.052