The area of a triangle with sides of lengths a and b and contained angle is

The area of a triangle with sides of lengths a and b and contained angle θ is A = 1/2 ab sin θ
(a) If a = 2 cm, b = 3 cm, and θ increases at a rate of 0.2 rad/min, how fast is the area increasing when θ = π/3?
(b) If a = 2 cm, b increases at a rate of 1.5 cm/min, and θ increases at a rate of 0.2 rad/min, how fast is the area increasing when b = 3 cm and θ = π/3?
(c) If a increases at a rate of 2.5 cm/min, b increases at a rate of 1.5 cm/min, and θ increases at a rate of 0.2 rad/min, how fast is the area increasing when a = 2 cm, b = 3 cm, and θ = π/3?