Question

How do I do this? 50 points, please answer

Answer 1

Check the picture below.

now, the midsegment of a triangle, besides being half the base, we have to bear in mind that is a "mid" segment, is a segment that lies half-way along the segments it touches.

so for the triangle above, well, the midsegment DE is cutting the segment BC it two equal halves, BE and EC, that means that $\stackrel{x}{BE}~~ = ~~\stackrel{8}{EC}$.