Help where to find bottom bearings

[Stakeknife]

Hello, my 4yr old sons bike decided to break and without instantly buying a new one I thought I would attempt fixing it. Its a mongoose scan R60 and from what I can see the bottom bracket bearings have gone.
So I have been on the lookout for 7x ball caged bearings but none seem to measure the external dimension of roughly 36-37mm.
Any help would be appreciated.

[Stakeknife]

I must add that I can see plenty 9x bearings 1/4 but they don't state a external size. I'm guess g this may be a standard fit?

[Justin S]

They should be 1/4 inch bearings and places like weldtite will get packs of loose balls to fit. I wouldnt bother with the cage. Its a bit bent and twisted and just use an extra ball or two in the cup instead. Use some reasonable grease to stop water ingress, preferably as the cups arent sealed against hose action.