00:01
We have an isosceles triangle with two sides that are 9 inches and then the other side is 8.
00:11
And we want to know the angle that the side of 9 inches makes with the 8 inches.
00:15
So we're looking with this angle here.
00:16
We can definitely use the law of cosines.
00:23
So let's call this c, and that means this will be a and b.
00:26
So we're looking at c squared, which is 9 equals to 8 squared plus 9 squared minus 2, 8 times 9, and then we have the cosine of c.
00:40
Well, the nice thing is is these two 9 squares will eliminate each other.
00:45
So that means i'm going to have this is 64.
00:48
So negative 64 is going to be negative 2 times 8 times 9 cosine of c...