Three dogs are pulling on a stick in different directions as shown in the figure. The first dog pulls with force F1 = 10i −20.4j + 2k N. The second dog pulls with force F2 = −15i − 6.2k N. The third dog pulls with force F3 = 5i + 12.5j N. a) What is the angle between F1 and F2? b) Find the point-normal equation of the plane containing F2 and F3 and the point P(1, 1, 1). c) Find the distance between the point P(1, 2, −3) and the plane in (b).