This math topic focuses on the Pythagorean Theorem, specifically identifying whether the missing side in a triangle diagram is a leg or the hypotenuse. It includes problems where students view a labelled triangle and determine the nature of the specified side. The skill being practiced here involves applying knowledge of right triangles, such as recognizing the hypotenuse as the longest side opposite the right angle and identifying legs, which are the two shorter sides that form the right angle. This set of problems serves as an introduction to the broader concept of the Pythagorean Theorem.