Uses of Computers at "Finding of Theorem of Angle at the Circumference" in Mathematics of a Secondary School

Computers were used for the guidance of "Finding of Theorem of Angle at the Circumference" in a Secondary School. Softwares on the market are used for the computers. The consciousness and understanding of students were compared the classes of used computers and those of unused. It was effective for classes of used computers in this study as follows. (1) It was reduction the drawing time of figures. So, students could have enough time to consider. (2) Students could have a kind and perfect explanations till they could understand them correctly. But, many problems were involved as follows. (1) They did not have enough hand processes in concrete examples. (2) It would be better for them not to use computers in the theoretical process forming a subject