Geometry Concepts

This is a practice app designed for learning plane geometry. It transforms abstract theorems into interactive, hands-on exercises where users can drag shapes, select logical reasoning steps, and correct common errors. 【Draw】 Drag yellow points on five types of geometric figures: triangles, circles, parallel lines, similar triangles, and coordinate-based shapes. As a shape approaches a configuration relevant to a theorem, the right side of the screen displays the corresponding notation and measurements—such as right-angled triangles, the inscribed angle theorem (inscribed angle is half the central angle), parallel lines (corresponding angles are equal), similar triangles, perpendicular lines, etc. 【Proof】 You are presented with a geometry problem and a set of reasoning steps. Select them in the correct order—do not guess. Topics cover inscribed angles, parallel lines, right-triangle similarity, and angle bisectors. Points are awarded for correct choices and deducted for incorrect ones. 【Fix】 First, view an incorrect proof step, then identify the actual error from the given options. Once the correct error is selected, the correct notation is displayed. Addresses common errors such as misidentifying corresponding sides, confusing exterior angles with interior angles, mistaking parallel transversals for midlines, and misapplying the projection theorem. 【Calculation】 Practice problems involving similar triangles' corresponding sides, parallel transversals, and area ratios. You can input fractions (e.g., 2/3), and the system will automatically calculate the missing value. A bar chart on the right compares the two quantities.