This math topic focuses on identifying the slope of lines that are perpendicular to a given line shown on a graph. Each problem presents a graph with a line, and the challenge is to determine which of the presented option lines has a slope that is perpendicular to the one shown. This is an introductory exercise to slopes and perpendicular lines, useful for understanding basic concepts in coordinate geometry and slope calculations. The topic is intended to develop skills in visual analysis of lines on a graph and application of the mathematical concept of perpendicular slopes.