Question 1375
the median from the central angle would divide the base in two, and would be the altitude as well.  (case of congruent triangles).

now, the hypotenuse is 7 for the smaller triangle. so, 
cos 30 = sqrt(3)/2 = base/hypotenuse...
so, base (of the sub triangle) = hypotenuse * cos 30

so, base of the original triangle = 2 * hypotenuse * cos 30
= 2*7*sqrt(3)/2
=7*sqrt(3)
= 1*1.732
= 12.124