To solve this expression, we need to use the trigonometric identity:

sin(a) cos(a) = 1/2 sin(2a)

Therefore, we have:

28sin(20) cos(20) = 28(1/2 sin(40)) = 14sin(40)

Now, we need to divide by sin(40):

(14sin(40)) / sin(40) = 14

Therefore, the expression simplifies to 14.