00:02
So with the information that we are given, we could draw out a certain triangle from this circle that would look like this, where this is the cord of the triangle, and this is the center point.
00:24
These are radii, and this is the angle.
00:27
I will label those.
00:29
So this cord is three centimeters.
00:32
These are radii, so they are four centimeters.
00:38
This is the center, and this is the angle theta that we are looking for.
00:47
Now, this definitely is not necessarily a right triangle.
00:54
So what we want to do is turn it into two right triangles that we can work with using trig ratios.
01:02
So we are going to split this into right along the middle with a line that's perpendicular to the cord.
01:11
See, right angles here.
01:15
And this angle would be theta divided by 2, and the same would apply here.
01:23
And we can just work with one of these two right triangles, find the value of theta over 2, and then just multiply by 2 to find theta.
01:33
So let's work with this top right triangle.
01:38
And there's one thing we need to notice as well...