#1**+1 **

A segment drawn parallel to the base of a triangle splits the sides proportionately

In triangle AXC....since segment ZY is parallel to base XC..so...

XZ : ZA = YC : AY

4 : 8 = YC : AY

1 : 2 = YC : AY

And in triangle ABC.....segment XY is parallel to base BC...so...

BX : AX = YC : AY

So

BX : AX = 1 : 2

BX : [ XZ + ZA ] = 1 : 2

BX / [ 4 + 8 ] = 1 : 2

BX / 12 = 1 : 2

So BX = 6

CPhill Oct 17, 2018