Answer:
[tex]4.3\ km[/tex]
Step-by-step explanation:
we know that
Applying the law of cosines
[tex]c^{2}=a^{2}+b^{2}-2(a)(b)cos(C)[/tex]
we have
c-----> is the distance between Amanda and Angela
[tex]a=10\ km[/tex]
[tex]b=12\ km[/tex]
[tex]C=20\°[/tex]
substitute the values
[tex]c^{2}=10^{2}+12^{2}-2(10)(12)cos(20\°)[/tex]
[tex]c^{2}=18.4738[/tex]
[tex]c=4.3\ km[/tex]