00:01
In this question, we are going to solve the oblique triangle, starting with the law of cosines.
00:09
Typically, when we are given three sides of a triangle, we want to find the largest angle first.
00:18
The largest angle would be opposite the longest side, so we're going to solve for angle c.
00:28
Using the law of cosines.
00:31
And i will plug in the values we've been given.
00:35
16 squared equals a squared plus b squared minus 2 times a times b times b times cosine of c.
00:52
Now let's do some of the math and we want to be careful to follow order of operations.
00:58
Start with 16 squared on the left.
01:08
On the right, let's add 10 squared plus 12 squared.
01:19
Let's multiply 2 times 10 times 12.
01:31
Next, let's subtract 244 from both sides.
01:47
Divide both sides by negative 240 and take the inverse cosine of both sides to find the measure of angle c...