From the markings on the diagram, we can tell E is the midpoint of BC and D is the midpoint of AC. We can apply the triangle midsegment theorem: ED = ½BA. Substituting in the expressions for the lengths and solving for x, we get x = 5. Now, since BE = x, then BC = 10.
Triangle midpoint theorem states that the line segment which joins the midpoints of two (2) sides of a triangle is parallel to the third side, and it's congruent to one-half of the third side.
By applying the triangle midpoint theorem, we can find the value of x:
ED = ½BA
x + 2 = ½(4x - 6)
2x + 4 = 4x - 6
4x - 2x = 6 + 4
2x = 10
x = 10/2
x = 5.
BC = x + x
BC = 5 + 5
BC = 10.
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