21. Find the distance between a point (zo, yo, zo) and the plane az+by+cz d A) 6, B) 4, C) 4//35, D) 2/3, E) None of the above 22. See Section 12.6 23, (Section 13.2) A projectile is fired with initial speed s m/s at the angle α to the horizontal. Find the maximum altitude. (Note that g 9.8m/s2) A) 43.8, B) 63.8, C) 66.8, D)100, E) None of the above 24. Find the volume of the portion of the cone z = V x2 y2/c below the plane z=a. A) Ï/3, B) Ï/V3, C) 9T, D) 3TV3, E) None of the above 25. Find the absolute maximum of f(x, y) subject to the constraint G(x,y) = 0. A) -6, B) 0, C) 6, D) 9, E) None of the above