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Answer:
18.6cm
Step-by-step explanation:
there is a theorem that states that the midsegment of a triangle (midpoint to midpoint, in this case X and Y) is half of the base (in this case BC)
when applied to the triangle shown:
XY= 1/2 BC
substitute to get
XY=1/2*6.4
XY=3.2
perimeter of BCYX
=XY+YC+CB+BX
=3.2+4+6.4+5
=18.6cm
hope this helps