Q:

The figure below shows a transversal t which intersects the parallel lines PQ and RS: Write a paragraph to prove that the measure of angle 4 is equal to the measure of angle 8.

Accepted Solution

A:
There are many ways to prove this, but the quickest and easiest way is to use the property of corresponding angles. If two lines are parallel with a line intersecting them both, their corresponding angles formed by the intersecting line are equal.
In this case, the corresponding angles are:
1 and 5
2 and 6
3 and 7
4 and 8
Since angle 4 and 8 are corresponding angles, they are necessarily equal.