This resource focuses on deriving the equation of a circle, linking it to the Pythagorean Theorem and distance formula. Students will engage in guided derivations where they will apply the distance formula between the center of the circle and a point on its circumference to express it in standard form. The resource includes sections for activating prior knowledge, a step-by-step derivation process, and conceptual reasoning related to the geometry of circles. Additionally, it features formative assessments where students identify key features of circle equations, analyze errors in given examples, and convert general form equations to standard form through completing the square.