Since there are 4.5*10^2 grams of trash per day per person, we multiply that by 3.2*10^6 for everyone in the US and then multiply that by 365 to get how much in a year, which is <span>525600000000 or 5.256*10^11 (I think it's 11)</span>
You are told that the angle the shape makes is 90 hence its a quarter of the circle so you just find the area of the full circle and divide by 4 (6^2*pi)/4 36pi/4 9pi which is around 27 2 Sig fig
