Answer:
25[tex]\pi[/tex]
Step-by-step explanation:
[tex]\pi[/tex]r^2 is the formula for a circle (in this case, a circular rug)
and we would set it equal to 84 (since we are trying to get the biggest size possible).
We would isolate r so that r^2 = 84/[tex]\pi[/tex], and r would be around 5.17219.
If we were going by rounding 5 would be the largest radius possible and the radius would be 25[tex]\pi[/tex] or about 78.5398 units.
