The area of a circle is 28.26 square centimeters. what is its diameter (use 3.14 for pi)?

Can someone check if i did this right since i really want to make sure it’s correct. if you do you so much

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.

Can some one me with these questions