Răspuns:
Explicație pas cu pas:
AM=(2/5)·AB, deci BM=(3/5)·AB; BN=(3/5)·BC, deci CN=(2/5)·BC;
CP=(2/5)·CD, deci DP=(3/5)·DC; DQ=(3/5)·AD, deci AQ=(2/5)·AD.
Atunci AM/BM=2/3=AQ/DQ, atunci dupa teorema Thales, ⇒MQ║BD.
Dar si CN/BN=2/3=CP/DP, deci NP║BD, Atunci MQ║NP.
Analog se arata ca MN║AC║QP, deci MNPQ este paralelogram.
