The purpose of this quasi-experimental quantitative study was to investigate the potential effect that blended learning has on student achievement in high school math. The theoretical framework used for this study was constructivism theory. The constructivism theory focuses on the idea that learning is a process where students build new knowledge from prior knowledge. The research questions examined the effect the instructional delivery method has on student achievement among high school students. Specifically, at the study considered mean differences in the SAT Suite of Assessment test scores that existed between the independent group (instructional delivery method) and the dependent group (SAT Suite of Assessment test scores). Student scores from the PSAT10, NMSQT, and SAT were utilized to determine differences in these scores. This study included 2022-2023 students classified as juniors in a school district located in Illinois. A mixed-between within-subjects ANOVA was utilized to determine the statistical difference in test scores across all three assessments. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]