As per the question, the glossary provided in the textbook would help find the definition of word 'isosceles' as it contains a list of terms in that particular domain or context of the book(knowledge) along with their definitions. A glossary usually is given at the end of a book and contains the list of words or terms that are either unfamiliar or specialized with a purpose to help the students contextualize the meaning of those words and understand the text better. Thus, <u>option B</u> is the correct answer as glossary would help confirm the meaning of the term 'isosceles' and understand it better.
