a^2 = a_c * c = 3*15 = 45
a = 3 sqrt 5
b^2 = b_c * c = 12*15 = 180
b = 3 sqrt 20
S = ab/2 = 3*3*sqrt(5)*sqrt(20) / 2 = 3*3*sqrt(100) / 2 = 45
a^2 = a_c * c = 3*15 = 45
a = 3 sqrt 5
b^2 = b_c * c = 12*15 = 180
b = 3 sqrt 20
S = ab/2 = 3*3*sqrt(5)*sqrt(20) / 2 = 3*3*sqrt(100) / 2 = 45