How do you prove that EF || AB ?

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1 Answer
Apr 29, 2018

See the Explanation:

Explanation:

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In #triangle ADM,#
#angle A + angle M = angle D = alpha + beta#

Given #angle A = alpha : #
#alpha + angle M = alpha + beta#
# => angle M = beta#

# EM # is #"transversal" # crosses # AB and EF, angle M = angle E = beta #
#=> AB " || " EF #