For the triangle shown, a = 200 mm, b = 250 mm, and e = 300 mm. Define a, b, and e as varnables, and then: (a) Caleulate the angle y (in degrees) by substituting the variables in the Law of Cosines. (Law of Cosines: c? = a' + b - 2abcosy) (b) Calculate the radius r of the circle inscribed in the triangle using the formula r = a+b-ctan( (c) Caleulate the radius r of the circle inscribed in the triangle using the for- mula r- s(s -a)(8 b(s-c) where s- -(a i bie).