00:01
So ultimately our goal is to find angle a in this triangle.
00:03
So i would probably start by drawing a triangle.
00:05
So if we have triangle a, b, c, let's go ahead and label what we've been given.
00:10
So we know that angle c is 36 degrees, side a, b is equal to 21, and side a c is equal to 30.
00:16
So our ultimate goal is to find angle a.
00:18
However, right now with the given measurements, by using our large signs, we can find angle b.
00:24
So by using the large signs, we'd have the sign of angle c, which is 36 degrees, divided by its opposite side, which is 21, this will equal to the sign of angle b divided by its opposite side, which is 30.
00:35
So let's first start by solving for angle b.
00:38
So we would cross multiply.
00:40
So we would have 30 times the sign of 36 degrees divided by 21.
00:45
And this will equal to the sign of angle b.
00:48
Or actually, in this case, i'm going to change my mind.
00:51
We're not going to cross multiply.
00:52
We'll just multiply both sides by our denominator.
00:54
So now we can go ahead and solve for angle b by taking inverse sign of both sides.
01:00
So we're going to have the inverse sign of 30 times the sign of 36 degrees divided by 21.
01:06
And again, this will give us the measure of angle b.
01:08
So if we do 30 times the sign of 36 degrees divided by 21, you'll find that angle b would be equal to 57.
01:18
And i'll round two places after the decimal.
01:21
Point one, one.
01:22
Now, you have to be careful.
01:24
So if this is 57 .11, we could find angle a.
01:27
So to find angle a, we would do 180.
01:30
Minus 36 minus 57 .11.
01:33
Because remember, all the angles in the triangle add up to 180.
01:36
So 180 minus 36 minus 57 .11 would equal to 86 .89 degrees.
01:44
Now, the one thing you have to be careful for your large signs is sometimes when you find the angle value at you, sometimes you could have two potential answers...
