Answer all questions u so much i'm sooo ergent it will me so much u so much /; )

What is the approximate circumference of the circle shown below?

3.4a=57.8 what is the the value of a

In stepmber, daniel and justin opened a business. during their first three months of business, their average monthly profit was $51. if during their first month, they lost $29, and during their second month, they gained $115, what was their profit or loss for their third plzzz i will give you 299 points