Question

in fig.6.13 BA||ED and BC||EF . show angle ABC+ANGLE DEF=180°

Answer 1

If line FE is extended to join line AB at point G, angle FGB and angle ABC become supplementary angles because BC||EF = BC||GF.
= angle FGB + angle ABC = 180°
angle FGB = angle DEF since DE||AB and joined by line EG.
Therefore, angle DEF + angle ABC = 180°.

Answer 2

Hi mate pls refer to the picture. I hope it helps you