NCERT Solutions for Chapter: Lines and Angles, Exercise 1: EXERCISE 5.1

If two adjacent angles are supplementary, they form a _____ pair.

If two lines intersect at a point, then the _____ opposite angles are always equal.

If two lines intersect at a point, and if one pair of vertically opposite angles are acute angles, then the other pair of vertically opposite angles are _____ angles.

In the adjoining figure, angle $AOD$ and which other angle form obtuse vertically opposite angles? $\left(EOC /BOE /BOC\right)$

In the adjoining figure, $\mathrm{\angle }\mathrm{E}\mathrm{O}\mathrm{A}\mathrm{}$ and which other angle form adjacent complementary angles? $\left(\mathrm{AOB} / \mathrm{COD} / \mathrm{EOD}\right)$

In the adjoining figure, $\mathrm{\angle }\mathrm{E}\mathrm{O}\mathrm{B}\mathrm{}$ and which other angle form equal supplementary angles? $\left(\mathrm{EOC} / \mathrm{AOE} / \mathrm{EOD}\right)$

In the adjoining figure, name the unequal supplementary angle to both the angles $\mathrm{\angle }DOA$ and $\mathrm{\angle }COB. \left(COD/AOB/AOE\right)$.

In the adjoining figure, name the adjacent angle to $\angle \mathrm{COD}$ such that they do not form a linear pair. $\left(\mathrm{COB} / \mathrm{AOE} / \mathrm{EOD}\right)$