Please help, show steps! Both b and a. Thank you so much :))

Question 12) A) A ladder 5 m long rests against a vertical wall. If the top of the ladder is sliding down at a speed of 40 cm/s, how fast is the angle of elevation changing when the top of the ladder is 3 m above the ground? C) Determine the rate at which the surface area of a sphere is increasing at the instant when the radius is 87.0 cm, and the radius is increasing at the rate of 1.9 cm/s. Use A = 4mm/2 and TT = 3.14, and round your answer to four decimal places