Find the following trigonometric values.
Express your answers exactly.
cos 5pi/4
sin 5pi/4

Find the solution of this system of equation -7x+y=-20 9x-3y=36

Does the point (1, sqrt 7) lie on circle shown.

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?