Getting a ProductID from a VariantID ONLY.-Collection of common programming errors

Via URL, my application is being given a Product’s VariantID, but NOT a product id.

I’m using a WebService Soap Client to access the Commerce Server, as well as a CatalogContext.

How do I retrieve information on the product, when you only have a VariantID?

or, how do I retrieve a productID via a VariantID?

getProduct() and getVariant() require a VariantID AND a ProductID.

Thanks