00:01
So whenever i have two parallel lines that's cut by a transversal.
00:04
A transversal is just a line that cuts through two or more lines.
00:07
So two parallel lines cut by a transversal, i have a couple of things that are true.
00:12
I know that alternate interior angles are equal.
00:16
Corresponding angles are equal, matching corners.
00:19
And i also know that alternate exterior angles are equal.
00:22
Okay.
00:23
So here i'm looking at angle six and angle four.
00:26
What's their relationship? okay, six and four.
00:29
They're not alternate interior, but i do know that four is equal to angle five because they are alternate interior.
00:43
Okay, what do i know about five and six then? well, angle five plus angle six, they add, they form a straight line, so they add to 108 degrees...