Answer:
C
Step-by-step explanation:
Using the law of cosines then cosΘ is the following quotient
cosΘ = [tex]\frac{a^2+b^2-c^2}{2ab}[/tex]
where a = 5.8, b = 10.5 and c = 10.9
cosΘ = [tex]\frac{5.8^2+10.5^2-10.9^2}{2(5.8)(10.5)}[/tex]
= [tex]\frac{33.64+110.25-118.81}{121.8}[/tex]
= [tex]\frac{25.08}{121.8}[/tex] = 0.21 → C