Question

Law of cosine. Please help

Answer 1

Answer:

B) 41.7

Step-by-step explanation:

Let $a=25$, $b=32$, and $c=37$. Use the Law of Cosines equation to find angle A=x which is directly across from side $a$:

$\displaystyle \cos(A)=\frac{b^2+c^2-a^2}{2bc}\\ \\\cos(A)=\frac{32^2+37^2-25^2}{2(32)(37)}\\ \\\cos(A)=\frac{1024+1369-625}{2(1184)}\\\\\cos(A)=\frac{2393-625}{2368}\\ \\\cos(A)=\frac{1768}{2368}\\\\A=\cos^{-1}\biggr(\frac{1768}{2368}\biggr)\\ \\A\approx41.7^\circ$

Therefore, the correct answer is option B, which means you were right!