00:01
Okay, first step, let's find this angle here, alpha.
00:05
Take this triangle, and i can use cosine.
00:10
Cosine of alpha is adjacent, 3 over hypotenuse, 6, a over h.
00:18
And that can work out on a calculator, or you may know it, one half gives you 60 degrees.
00:27
So alpha then is 60 degrees.
00:30
Now, let's take the big triangle here, 3 here and 7.
00:38
And we're going to find this angle here.
00:43
I'll call it theta, and theta will be here...