biVector forum

Hodge dual question

In Guided tour of PGA by @LeoDorst (version 1.15, July 6, 2020) Hodge dual * is defined in eq(125). The next eq(126) shows what *X is where X is a the Euclidean factor of the blade X. I don’t see how to apply the definition of Hodge dual from eq(125) to calculate *X. Can someone help?