a triangle has two of its corner points A = (1.0,01) and B = (3,0,0). The third corner C lies on line L: (x, y, z) = (1,2,3) + t (0,0,1)

Determine all possible C for which the area of the triangle is equal to L

so i get that arean should be 1/2sqrt((2+t)^2+(4+2t)^2+(4+2t)^2) and i get wrong answer.