Draw a cube and Cartesian axes. All points of the cube lie in the (+,+,+) octant of the coordiante system. One vertex of the cube is at (0,0,0), the point called O. The vertex that is diagonally across from O on the square in the xz plane is point A. The vertex that is diagonally across from O on the square in the yz plane is point B. The vertex that is diagonally across the cube from O is called C.

(a) Determine the angle (in degrees) between the vectors OA and OB.

(b) Determine the angle (in degrees) between the vectors OA and OC.