So this expression right here can be rewritten as the negative of the integral between negative 4 and 0 f of t dt. And now this expression right over here is the area under f of t, or in this case f of x, or the area under f, between negative 4 and 0. So it's this area right over here. And we have to be careful because this part over here is below the x-axis, so this we would consider negative area, we would think of it in integration terms, and this would be positive area. So the total area here is going to be this positive area minus this area right over here. So let's think about what this is. So this section over here, we did this in part a actually, this is a quarter circle, so it's 1 fourth, so these are both quarter circles, so we could multiply 1 fourth times the area of this circle, the area of this circle, of this entire circle, if we were to draw the entire thing all the way around, it has a radius of 3, so the area of the entire circle would be pi times 3 squared, or it would be 9 pi.