 So, let's use ten. Ten theta is equal to opposite over adjacent. Okay. Again, we decided to be here. Now theta, remember this is a general term. I'm choosing this theta to be this but I could have easily chosen it to be that. Okay. So, we got ten theta, ten 41.4 is equal to opposite. Now, what's opposite from this angle? And when they say opposite, they're not talking about opposite angles. They're talking about the sides. Okay. These opposite adjacent and hypotenuse always refer to the sides. So, ten of 41.4 is opposite over adjacent. So, what's opposite from this? It's 4.1. And what's adjacent? What was the W we're trying to solve? We're assuming we didn't know what this was. So, this becomes W. So, what you do now is you go ten of 41.4, 41.4, ten, which is 0.88162 is equal to 4.1 over W. Now, you got to get W by itself. So, you cross multiply this up. So, you got W times 0.88162 is equal to 4.1. And you want to get W by itself. So, you divide by 0.88162. Divide by 0.88162. This kills this. So, 4.1 divided by 0.88162 is W is equal to 4.6505. Now, according to the sig figs, these guys are going to vary a little bit from the answer we got previously, but we don't care because we only want to take it to one sig fig anyway. So, this becomes 4.7. You follow? You know what? Let's use this angle to find out W. So, let's assume we didn't know what W was. Again, we did it two different ways. We got the same answer. Let's do it one more way to get the same answer, convince ourselves that it doesn't make a difference. As long as we're using information that we have that fits into the equations, we can solve the problem. So, let's use this angle, beta, to find out what W is. And assume we didn't know this. So, let's erase it just for the moment. So, if we use this angle, W ends up being opposite beta. So, we're looking for one of these guys that has the opposite. Well, sine has opposite and tan has opposite. So, we can use sine or tan. It's up to us really. Let's use tan. Actually, we use tan, we use cos. Let's use sine. So, we've got sine of beta is equal to opposite over hypotenuse, which is 6.2. So, again, what we're going to do is we know what beta is. Beta is 48.6. So, let's sub that indirectly. So, that becomes sine of 48.6. So, sine of 48.6, so 48.6, sine is 0.750111 is equal to W over 6.2. And then we're going to cross, multiply the sucker up because we want to get W by itself. So, that times 6.2 is W is equal to 4.65069, blah, blah, blah. Again, the decimals over here differ a little bit from what we got before, but we don't care because we're again going to one decimal place. And this rounds up to 4.7. Again, we got 4.7. So, it doesn't make a difference which formula you use as long as you know two of the variables here and you're solving for the third one. So, keep in mind that to solve for one unknown, you need one equation. To solve for two unknowns, you need two equations. To solve for three unknowns, you need three equations and so on. Since we only had one unknown, we could have used any one of these and we did and we always got the same answer. Now, what we're going to do is probably cover congruent triangles. So, we'll just talk about that real quickly, okay? Good luck. Practice these. Hopefully, I'll get some questions up on my site soon. So, you can do those or just go through your textbook and try them out. Good luck.