To find r, you need to isolate it. pi*r^2*60=18,840. divide 18,840 by 60, then pi, it comes out at 100. Now find the square root to get 10
r=10
1.4 because you divide 7.45 by 5.51 and you get 1.35 which would be rounded to 1.4
Answer:
Quad=4 so you need to round it off
