The SOLARO Study Guide is designed to help students achieve success in school. It is a complete guide to be used by students throughout the school year for reviewing and understanding course content, and for preparing for assessments. The content in "Texas High School Geometry" is specifically aligned to the Texas state standards for those who intend to have students complete school mathematics by the end of high school. Each Class Focus includes the following sections: Definitions, Axioms, and Postulates; Working with Triangles and Polygons; Measurement; and Coordinate, Circle, and Line Geometry. To create this book, teachers, curriculum specialists, and assessment experts have worked closely to develop the instructional pieces that explain each of the key concepts for the course. The practice questions and sample tests have detailed solutions that show problem-solving methods, highlight concepts that are likely to be tested, and point out potential sources of errors. Enhanced treatment of concepts, more practice sections, and additional learning tools are found in the accompanying online version of SOLARO which may be accessed through the web or on mobile devices.