Given the intersection of two chords, find the missing length

The video tutorial discusses the intersection of two chords and the relationship between their lengths. It explains that the product of the lengths of segments of one chord is equal to the product of the lengths of segments of the other chord. The tutorial demonstrates solving an equation to find an unknown variable and emphasizes the importance of taking notes during class.

What does it mean for products to be congruent in this context?

Why is it important to take notes during class discussions on this topic?