00:01
All right, we're given this origami problem that has to do with a bunch of square paper that's been folded a bunch of times.
00:08
We're asked to find congruent angles.
00:10
So the first thing to remind ourselves of what congruent means.
00:14
So congruent is exactly equal.
00:18
And when we're talking about angles, that's really, really important because some of the angles can look similar.
00:24
But based on the relationship with the, in this case, the folding, it's going to really make a big difference in terms of it being.
00:30
Identical.
00:32
So let's take a look at each of these, each of these different pairs.
00:35
There's angle i -r -s and angle m -r -o, then angle o -n -t, and angle m -t -n -t -n, angle m -k -r, and angle o -a -r, and then angle u -r -c, and angle t -r -o -t -r -o.
01:01
Now the other thing to remember here is when we're naming our angles, i'm going to just show an example here with my own.
01:11
We'll call this xyz.
01:14
When you name an angle, the angle goes in order with the vertex, like that middle point being the middle dot here.
01:24
So this would be like going down and then across.
01:29
You could also name this angle z y x.
01:35
That would be fine as well.
01:36
It just means that as you were reading it, it would go the opposite direction.
01:39
You go this way and then that way.
01:42
But in both cases, you can see that the y, the vertex is in the middle.
01:45
So when we're finding angle i -r -s, it means that we start at i, we continue into r, and then go out to s.
01:56
So here's our angle, angle i -r -s.
02:00
Mro, same idea.
02:03
I'm going to continue to use blue just so we can keep it consistent here.
02:09
So m travels in, and then here's r in the middle, and then there's o.
02:15
Now, things you'll notice.
02:17
The first thing is that mro is actually a right angle.
02:21
So we can already see that i -r -s is acute and m -r -o is a right angle.
02:28
So this definitely does not work.
02:30
These are not congruent.
02:33
You can say not equal or not congruent.
02:35
It doesn't matter.
02:37
So now let's look at o -n -t and m -t -n.
02:40
So o -n -t, i'll use red...