Answer:
<A ≈ 45 degrees
<B ≈ 57 degrees
<C ≈ 78 degrees
Step-by-step explanation:
Hi there!
1) Find <C with the law of cosines
Typically, we want to solve for the angle opposite the largest side first.
Law of cosines: [tex]cosC=\frac{a^2+b^2-c^2}{2(a)(b)}[/tex]
Plug in given values
[tex]cosC=\frac{5^2+6^2-7^2}{2(5)(6)}\\cosC=\frac{1}{5}\\C=cos^-^1(\frac{1}{5} )\\C=78[/tex]
Therefore, <C is approximately 78 degrees.
2) Find <B with the law of cosines
[tex]cosB=\frac{a^2+c^2-b^2}{2(a)(c)}[/tex]
Plug in given values
[tex]cosB=\frac{5^2+7^2-6^2}{2(5)(7)}\\cosB=\frac{19}{35}\\B=cos^-^1(\frac{19}{35})\\B=57[/tex]
Therefore, <B is approximately 57 degrees.
3) Find <A
The sum of the interior angles of a triangle is 180 degrees. To solve for <A, subtract <B and <C from 180:
180-57-78
= 45
Therefore, <A is 45 degrees.
I hope this helps!
