Questions & Answers about Ta proporcja jest tu bardzo dobrze widoczna.
Why do we use the adverb dobrze instead of an adjective before widoczna?
Why is the word for "visible" written as widoczna here?
It has to match the gender of the noun it describes. Proporcja (proportion) is a feminine noun, so the adjective takes the feminine nominative ending -a to become widoczna.
Could I use the word widać (it can be seen) to express the same idea?
Yes, but it changes the grammar completely! If you use the impersonal verb widać, the sentence becomes Tę proporcję bardzo dobrze tu widać. The subject ta proporcja changes to the accusative case (tę proporcję) because it acts as the direct object of widać.
Can I use tutaj instead of tu?
Absolutely. Tu and tutaj both mean "here" and are perfectly interchangeable. Tu is just a shorter form that flows very naturally in the middle of a sentence like this.