The height of the third rectangle is going to be the function evaluated at its left boundary, so f of 2, so plus f of 2 times the base times delta x. And then finally, the area of the third rectangle is the function. The height is a function evaluated at 2.5. So plus, that's a different color than what I wanted to use. Let me use that orange color. So plus the function evaluated at 2.5 times the base. This is going to be equal to our approximate area.