91Ó°ÊÓ

Pair of opposite angles formed by intersecting lines.

Name the points of line segments in the given figure

Since the lines AB and CD are intersecting lines therefore the angles 1 and 3 are vertically opposite angles. Hence both the angles are equal.

Therefore, the answer is.

As from the figure, the angles 2 and 4 are on the same side of the intersecting lines and angle 3 is the whole angle so $∠2+∠4=∠3$

If $a=b+c$ and $c>0$ then $a>c$. As $∠2+∠4=∠3$and $4>0$so $∠3>∠2$. It can be written as $∠2<∠3$.

Thus, the answer is $<$.

When two lines are intersecting lines then the opposite angles are equal in measure. Therefore, the angles 1 and 3 are equal angles.

As from the figure, $∠2+∠4=∠3$. From part (a) $∠1=∠3$. Therefore, $∠2+∠4=∠1$.

If $a=b+c$ and $c>0$ then $a>c$. As $∠2+∠4=∠1$and$4>0$so $∠1>∠2$.

Thus, the answer is $>$.