The study determined the efficacy of origamibased instructional model (OBIM) on teaching proofs of mensuration theorems: A panacea for college students’ understanding of mathematical theorem. Population of the study was 2461 SSS III students in the public secondary schools in Awgu Education Zone, Enugu State, Nigeria. The study was guided by four research questions and four null hypotheses. The hypotheses were tested at 0.05 level of significance. Multi-stage sampling technique was adopted, through which 149 subjects were randomly sampled and used for the study. Mathematics Achievement Test (MAT) instrument containing essay items and developed by the researcher was used for data collection. The MAT was subjected to lecturers in mathematics Education and Measurement and Evaluation areas for face validation and its reliability formula yielded 0.79. The data collected with the MAT were analyzed using mean and standard deviation (SD) to answer the research questions while ANCOVA statistic was used to analyze the hypotheses at 0.05 level of significance. Results of the study revealed that OBIM is effective in enhancing students’ understanding proofs of mensuration theorems. Before treatment there was no significant difference between experimental and control groups (P  .05) while after treatment there was significant difference between the duo in which the experimental group performed significantly higher than their counterpart in control group. Moreso, before treatment, there was significant mean difference in performance between the males and females in experimental group (P  .05), while after treatment there was no significant mean difference between the duo which means that the use of OBIM is effective in bridging the gap in gender inequality in mathematics performance. It was recommended to teachers, examination agencies (WAEC & NECO), authors of maths textbooks and curriculum developers to incorporate the use of OBIM in planning and execution of mathematics instruction especially in teaching proofs of mensuration theorems.

Keywords : Origami, Instructional Model, Mensuration Proofs, Theorems, Mathematics and Students.