Answer:
[tex]\boxed{b.\:\:\:\sqrt{13}}[/tex]
Step-by-step explanation:
Let the third side of the triangle be [tex]h\: units[/tex].
We can apply the cosine rule to find [tex]h[/tex].
[tex]h^2=3^2+4^2-2(3)(4)\cos(60\degree)[/tex]
We evaluate to obtain;
[tex]\Rightarrow h^2=9+16-24(\frac{1}{2})[/tex]
[tex]\Rightarrow h^2=25-12[/tex]
[tex]\Rightarrow h^2=13[/tex]
We take the positive square root of both sides to obtain;
[tex]\Rightarrow h=\sqrt{13}[/tex]
The correct answer is B.
