That distance is one minus x over two. That distance is one minus x over two. That distance is one minus x over two. So that is one minus x over two is equal to the radius. And so what would be the area of, what would be the area of this side right over here? Well, if it was a full circle, it would be pi r squared, but it's a semicircle, so it's pi r squared over two. So let me write this.