we know that one angle is 30∘ and another is 90∘ and the sum of all the angles in a triangle is 180∘ so we know that the third angle = 180 - 30 - 90 = 60∘ and so the triangle is a 30-60-90 degree triangle and since ¯CA= 6 then ¯CB=¯CA⋅2=12 and ¯AB=¯CA√3=6√3 and the area is 6⋅6√32=6⋅6⋅√32=36√32=18√3