The answers to the mathematical problems in "Discovering Geometry: An Investigative Approach" are available to registered users on the Slader education website. Registration is free and requires a name, email address, graduation date and name of a high school.
The geometry problem solutions available on the website are for exercises found either online or in a physical textbook. The site also provides a tracking record of how well the questions are being answered and where to find further information about the mathematical methods utilized if needed. Customers who purchase a professional registration to the website can access the information without any advertisements cluttering the screen page.