Given: zabc and zfgh are right angles; ba || gf; bc gh
prove: a abc afgh
step 1: we know that zabc 2 zfgh because all right angles
are congruent.
step 2: we know that zbac gfh because corresponding
angles of parallel lines are congruent.
step 3: we know that bc gh because it is given.
step 4: a abc afgh because of the
asa congruence theorem.
aas congruence theorem.
third angle theorem.
reflexive property.