Given:
A figure in which a transversal line t intersect the two parallel lines a and b.
To find:
The measure of the numbered angles.
Solution:
If a transversal line intersect the two parallel lines, then
1. Corresponding angles are equal.
2. Alternate interior angles are equal.
3. Alternate exterior angles are equal.
Now,
(Linear pair)
![m\angle 1=180^\circ-99^\circ](https://img.qammunity.org/2022/formulas/mathematics/high-school/vue1smkpp6fup7a48xwi9uz8xskorhy4ad.png)
![m\angle 1=81^\circ](https://img.qammunity.org/2022/formulas/mathematics/high-school/194k6fr7vjm89kn78y4tr2bdrq1w6022k7.png)
(Vertically opposite angles)
(Vertically opposite angles)
(Corresponding angles)
(Alternate interior angles)
(Alternate exterior angles)
(Corresponding angles)
Therefore,
.