SOLUTION: Colin, Nick and Jack are throwing a baseball around. Colin is 90 feet from Nick, Nick is 80 feet from Jack and Jack is 110 feet from Colin. When Jack looks at the other two what i

Use the Cosine Law.



Or, alternatively, calculate the area of the triangle using the Heron's formula;


Then use another formula for the triangle area  S = , where "a" and "b" are any two sides 

and  is the included angle.