00:01
All right, so here we are solving a triangle.
00:02
So let's make a triangle.
00:04
Let's have this be angle a, angle b, angle c.
00:08
I know that angle a is going to be 60 degrees, and b is going to be 20 degrees.
00:15
Well that leaves, if this is 60 and 20, that's 80.
00:18
The sum of the triangle must be 180.
00:21
So this is not the scale at all, but angle c here must be then, well, so angle c is going to be 100 degrees.
00:33
Okay, and we also know what that a, side a is 5.
00:38
So if this side is 5, we can then use the law of sines that says the sine of the angle, so sine of 60 degrees over the side opposite it, so over 5, is going to be equal to, well, let's say sine of b, so sine of 20 degrees over the side opposite it, so over side b.
01:00
And therefore, what is b? well, you know that sine of 60 times b is going to be equal to then 5 times sine of 20.
01:06
We can cross multiply since we have two fractions that are equal to each other.
01:10
All right, so here we are.
01:11
So we get here that, well, sine of 60 times b, or b times sine of 60 degrees, is going to be equal to 5 times sine of 20 degrees.
01:25
And therefore, just dividing by sine of 60, which should, well, that's going to give us, that's going to give us b.
01:32
So putting that into a calculator, all right, is going to give us that our side b is going to be approximately 1 .97, just under 2...