Step-by-step explanation:
the formula to calculate a circumference is

(consider x as the diameter)
so I'll be noting the circumference as C alongside the circle's ranking
a.

b.

c.

hope I helped
Factored form - x= -1/2, -5/4
The exact answer would be <span>392.78
An estimated value could be either 390 or 393</span>
Answer:
1,215 i think please be right