A document discusses working with circles and provides geometry problems involving circles. It asks the reader to find values of x and y in a multi-step problem and explain each step. It also asks the reader to find two congruent triangles and explain why they are congruent. Additionally, it provides a geometry problem asking the reader to determine the perpendicular distance from the center of a circle to a chord, given the circle's diameter is 20 cm and the chord measures 12 cm.