I recently broke the tray in my RCA RMW712 oven. When I googled the replacement I found a single source for $66, more than the price of the oven. Fortunately they were out of stock, saving me that decision.
So I started searching by description, 9 1/2" diameter. Lots available in the circle platform style, but I finally found one in the three radial arm platform style required for the RCA oven.
https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
And for only $16. It arrived yesterday and fits just fine.
Problem solved.
Walt