Elspeth knows that PI r=9.42cm. What would she need to do to find the circumference?

Take that pi = 3.142

pi r = 9.42

r = 9.42/3.142 = 2.998

d = 2 x 2.998 = 5.996

Cricumference = 3.142 x 5.996 = 18.839 cm

You need to get the radius then multiply by 2 to get the diameter then you can get the circumference.