In the triangle ABC, extend AC to point F so that CF = 2 / 1Ac, D and E are the midpoint of edge AB and BC respectively. Prove DC = EF
Proof: ∵ D, e are the midpoint of edge AB, BC respectively
∵ de / / AC, de = 1 / 2Ac, and ∵ CF = 2 / 1Ac
The De is parallel and equal to CF
The quadrilateral cdef is a parallelogram
∴DC=EF
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