Question

Which pair of lines in the figure are parallel? Give reasons.

Answer 1

Given: In the figure, $\angle A={115}^0,\angle B={65}^0,\angle C={115}^{0}and\angle D={65}^0$
$\because \angle A+\angle B={115}^0+{65}^0={180}^0$
But these are co-interior angles,
$\therefore$ AD||BC
Similarly, $\angle A+\angle D={115}^0+{65}^0={180}^0$
$\therefore AB||DC$