When I was going through proof of Antiderivative theorem, I saw following step which comes when we apply Mean Value Theorem on Antiderivative $G$ of $f$.
$$G(x) - G(a) = G'(t)(x-a) = f(t)(x-a)$$
where $a\leq t \leq x$.
Does this result tells us something intuitive? Like, We can always express Riemann integration of function (whose Antiderivative exists) in terms of area of one rectangle.