This paper reports a study on the effect of using the Lakatosian heuristic method to teach the surface area of a cone (SAC) on students' achievement according to Bloom's taxonomy levels. Two groups of students (experimental and control) participated in the study. The experimental group (n = 20) was taught using the Lakatosian heuristic method while the control group (n = 36) was taught using the Euclidean deductive method. Both groups were given a pre-test and a post-test. Data analysis using two-way Analysis of Variance shows that both groups increased their scores within times (pre- and post-test) at a = 0.05. However, the experimental group scored higher than the control group within time and also displayed more positive higher-order thinking skills than the control group. It was concluded that the Lakatosian heuristic method would, in all likelihood, help students to learn the SAC better than the Euclidean method does.