Remark
Study the triangle carefully. It may not be exactly as you have drawn it, but it will work if you just follow the givens.
Givens
AC = 2
AB = 1
BC = sqrt(3)
Step One
Find Cos C
Cos(C) = adjacent / Hypotenuse
Cos(C) = BC / AB
Cos(C) = sqrt(3)/2
Step Two
Find Sin(A)
Sin(A) = opposite / hypotenuse
Sin(A) = AB / AC
Sin(A) = 1/2
Step Three
Find Cos(C) * Sin(A)
Cos(C) * Sin(A) = sqrt(3)/2 * 1/2 = sqrt(3) / 4 <<<< Answer