• The top 10% receive A’s. • The next 20% receive B’s. • The middle 40% receive C’s. • The next 20% receive D’s. • The bottom 10% receive F’s. Find the lowest score on the final exam that would qualify a student for an A, a B, a C, and a D.

The statement is and the reason is add 1 both sides.

Explanation:

The given equation is .

We know that according to the addition property the equation x=y and x+c=y+c are equivalent equations, where c is a constant.

So we can add 1 both sides in the given equation.

Now we can take LCM and we get,

The above step is the third step of the given proof. By follow the given steps we can prove that DE is parallel to AC.

Therefore, the missing step is addition of 1 on both the sides of the given equation.