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statement reason
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1.DEFG is a parallelogram 1.Given
H is where segment DF and EG intersect
2.@EDH+@HDG+@HGD+@FGH=180 2.def of parallelogram-consecutive
angles are supplementary
3. @HDG+@HGD+@DHG=180 3.def of a triangle
4. @HDG+@HGD=180-@DHG 4.subtraction post.
5.@EDH+ (180-DHG)+ FGH=180 5.substitution post from statements
#2,4
6.@EDH+@FGH=@DHG 6.addition and subtraction post.
subtracted 180. added @DHG