Technology enhancements of the past two decades have not successfully overcome the problem of low motivation in Kindergarten through Grade 12 (K-12). Motivation and math achievement have been identified as major factors contributing to the high school dropout problem (30-50% in traditional/online programs). The impact of extrinsic rewards on achievement and the dropout problem, however, remains a subject of debate. This dissertation seeks first to address this debate, through an investigation of reward system effectiveness in the blended learning environment, on at-risk students with varied intrinsic motivation factor scores. Next, the dissertation explores the importance of fit between students' reward perceptions and reward values when motivating student progress. To this end, the author has developed a new 6-factor motivation orientation model for students in blended learning environments, and a learner-configurable progress-based reward system (PBR) for Learner Content Management Systems (LCMS) based on this model. The hypothesized model was tested for fit with a sample of 353 at-risk high school math students in Miami, Florida. The PBR was developed based upon the findings from interviews with subject matter experts and students, factor and regression analyses used to test hypotheses about learner motivation and predict learner progress. Conclusions from the study informed the design of an integrated PBR. A 6-factor motivation orientation model was found to explain more of the variance (74%) in student motivation than earlier models. Contrary to Deci et al. (1999), hypothesis test results did not confirm adversarial extrinsic rewards/intrinsic motivation relationships. Furthermore, consistent with person-environment fit theory, learners demonstrated superior progress and achievement when extrinsic reward perceptions and values were well aligned. With critical input from flexible learning theorists, teachers, and students, the emerging PBR design may ultimately be integrated through mobile learning applications and social media, within LCMS solutions such as Blackboard, and systems commonly used in K-12, such as Apex. Although beyond the scope of the dissertation, the emerging Web-based design promises to play an important role in engaging a K-12 Community of Practice (CoP), consisting of telecommunications partners, game developers, retailers, and education stakeholders sharing a significant interest in future innovations that address the dropout problem.