A geometry textbook is an educational resource designed to teach the principles and concepts of geometry, a branch of mathematics that deals with shapes, sizes, and the properties of space. These textbooks typically cover topics such as points, lines, angles, triangles, circles, and polygons, providing definitions, theorems, and proofs to help students understand the material. In addition to theoretical concepts, geometry textbooks often include practical exercises and problems for students to solve. Many also feature illustrations and diagrams to visually represent geometric figures, making it easier for learners to grasp complex ideas and apply them in real-world situations.