Question

In the figure, prove that AB||EF.
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Answer 1

Answer:

angle ABC = angle BCE + angle ECD

50° = 20° + 30°

50° = 50°

( if alternate angles are equal then two lines are parallel )

so, AB||CD............(eq 1 )

angle FEC + angle ECD = 180°

150° + 30° = 180°

180° = 180°

( if sum of two adjacent angle is 180° then two lines are parallel )

so, EF||CD............(eq 2)

by eq 1 and 2

if AB || CD and EF || CD then AB || EF

( by Euclid's axoms 1st is parallel with 3rd and 3rd is parallel with 2nd then all will parallel with each other )

Step-by-step explanation:

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