On a map , Orlando is 178mm due south of Niagara Falls, while Denver is 273mm from Orlando and 235mm from Niagara Falls. From the triangle formed by these three citices , find the angle created at Denver. Solution cos ^2 D= (O^2 +N^2 -D^2)/2ON =(273^2 +235^2 -178^2)/2*273*235 =0.76432 cos D=0.76432 D=29.04 DEGREES.