A Toy Problem 3

Thanks for visiting NZMaths.
We are preparing to close this site by the end of August 2024. Maths content is still being migrated onto Tāhūrangi, and we will be progressively making enhancements to Tāhūrangi to improve the findability and presentation of content.
 

For more information visit https://tahurangi.education.govt.nz/updates-to-nzmaths

Part of a toy is made up of a block on top of another block. Both blocks are 6 cm by 8 cm. The top block rotates about its centre, X. 
toy.

In the diagram above, A is the midpoint of a shorter side of the top block; B is a corner of the top block; and C is a point on the edge of both rectangles; and.
 
The points A, B and C all move on a circle as the top block rotates. What are the radii of these circles?