since pi is irrational and it is used in the formula, we cannot give an exact answer except in terms of pi (we can give an aproxamation using 3.14 =aprox pi, but it is not exact)
ok circumfernce=2pir r=15 circumference=2pi15 circumference=30pi
exact=30pi cm if you want to aprox pi=3.14 then aprox circumfernce=94.2 cm
