Answer:
i dont know
Step-by-step explanation:
Answer:
It's 78.6
Step-by-step explanation:
I hope this helps you
Answer:
69
Step-by-step explanation:
The correct option is: 53.9°
<em><u>Explanation</u></em>
According to the below diagram,
is acute triangle, in which
and 
If we <u>apply cosine rule</u> here, then we will get.....

Now, plugging the given values, we will get....

So, the measure of
is 53.9°
Using the rule for 2x2 matrices,

the determinant for your matrix is