The purpose of this study is implementation of a structured inquiry learning model in instruction of geometry. The model used is a model with a quasi-experimental study amounted to two classes of samples selected from the population of the ten classes with cluster random sampling technique. Data collection tool consists of a test item questionnaire understanding of geometry and geometric perception of students towards learning using interactive learning technology. Post test data analysis begins with understanding the concept of geometry such analysis prerequisite test for normality test using Kolmogorov-Smirnov test and homogeneity test data using Levene test. Two mean difference test used was Kruskal Wallis k-independent samples of assisted program SPSS version 16. The results showed that students' understanding of the concept of geometry which acquire learning with structured inquiry model is significantly higher than the understanding of the concept of students who received conventional learning. Understanding the concept of geometry students with interactive learning technology is better than the understanding of the concept of students with conventional learning. There is a positive interaction between the applications of structured inquiry learning model by using interactive learning technology for students' understanding of the concept of geometry.