Julio considers the reduction of the triangle. what is the correct cross product that he should use to solve for the missing dimension? (8)(12) = 21x (8)(21) = 12x (12)(8) = 12x (12)(21) = 8x

For this case we observe that the triangles are similar.
 Therefore, we can use the following relationship:
 (12) / (21) = (8) / (x)
 From here, we can clear to know the value of the incognita x.
 
 the correct cross product that should be used to solve for the missing dimension is:
 (12) / (21) = (8) / (x)

You have to use division for this problem