ProveIt! Two-Column Proofs Practice Tool

Proof: Converse of Parallel Lines 4

line ABCD

ECD = 140 $\^o$

ABF = 40 $\^o$

line BF $\|\|$ line CE

1.

1.

FBC =

FBC

ABF = 40 $\^o$

FBC +

BCE =

FBC +

BCE

180 $\^o$ = 40 $\^o$ +

FBC

angle

FBC and

angle

BCE are supplementary

ABC =

ABF +

FBC

line BF $\|\|$ line CE

40 $\^o$ =

BCE

180 $\^o$ =

BCE + 140 $\^o$

ABC = 180 $\^o$

FBC +

BCE = 140 $\^o$ + 40 $\^o$ ;

FBC +

BCE = 180 $\^o$

line ABCD

BCD = 180 $\^o$

BCD =

BCE +

ECD

ECD = 140 $\^o$

140 $\^o$ =

FBC

ProveIt! by Michael Ferraro <mferraro@balstaff.org>.
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