Question 1076356
a^2=b^2+c^2-2bc cos A by Law of Cosines
a^2=565^2+480^2-2(565)(480)*cos 85
=502351.73
sqrt of that is A=708.8 ft.
-------------
check with law sines
a/sin 85=708.8/sin 85=711.5
b/sin b=711.5, use it to find the sin of the angle, and then take the arc sin to get the angle, which is 42.4 degrees
c/sin c=711.5, 565/711.5 is the sin of c, take arc sin, which is 52.6
The angles are 85, 52.6 and 42.4=180, as they should be.