Question 1101558
{{{(3.5)^2+(6)^2-(3)^2=49/4+36-9=(49+144-36)/4=157/4}}}
{{{2(3.5)(6)=42}}}
So,
{{{cos^(-1) (((3.5)^2+(6)^2-(3)^2) / (2(3.5)(6)))=(157/4)/42}}}
{{{cos^(-1) (((3.5)^2+(6)^2-(3)^2) / (2(3.5)(6)))=highlight(157/168)}}}