Calculating Moment of Inertia: A Figure Skater's Finale

[CaptFormal]

Homework Statement

A figure skater during her finale can increase her rotation rate from an initial rate of 1.14 revolutions every 1.86 s to a final rate of 3.13 revolutions per second. If her initial moment of inertia was 4.46 kg*m2, what is her final moment of inertia?

Homework Equations

The Attempt at a Solution

I thought that I could use some type of mathematical relationship between the revolutions per second and the inertia. However, I am not getting the correct value. Any help will be appreciated. Thanks.

 

[Kurdt]

Angular momentum is conserved.