No the circumference of the circle is not 56.52. According to the formula which is pi x diameter all you have to do is multiply 9 times pi which is 3.14. This would equal 28.26cm, not 56.52cm.
Circumference if the circle= 2πr or πd Substitute the diameter=9cm into second equation C=9π C≈9×3.14 C≈28.26 cm. As a result, it is false that the circumference will be 56.52 cm if the diameter eqaul 9 cm. Hope it help!