Problem Solving (PS) | Re: If EF is parallel to DG, the length of AB is half of that of AC, the

Given that AB=1/2AC. Triangle must be a 30-60-90 right angled triangle.
LACB=30 deg.,thereforeL DCG=30 deg.
Since CG=CD,LCGD=L CDG=75 deg.
EF is parallel to DG, thereforeLDEF=L CDG= 75 deg.
DE=EF
Therefore in triangle DEF,L E=75 andLEFD=L EDF=(180-75)/2=52.5
Answer C.

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