This math topic focuses on calculating the fraction of a circle covered by a sector, based on given sector areas and circle radii. It combines elements of geometry, specifically dealing with circle sectors, and fraction computation. Each problem presents a sector's area and the radius of the circle to which the sector belongs, requiring the learner to determine what fraction of the circle's total area is represented by the sector. Multiple-choice answers guide the learners to find the correct fraction, utilizing equations and understanding of circle geometry principles.