A rectangle is a relatively basic figure in geometry, and it is a special parallelogram, which refers to a parallelogram with one corner that is a right angle. But a rectangle and a parallelogram are different. A rectangle is an axisymmetric figure, which has two axes of symmetry; it is also a centrosymmetric figure, and the center of symmetry is the intersection of the two diagonals. In order to demonstrate the symmetry of the rectangle to the students, the geometric sketchpad courseware making tool can be used for dynamic demonstration. Let's learn the specific production skills below.
Geometric Sketchpad software access address : http://www.jihehuaban.com.cn/xiazai.html
Geometric Sketchpad demonstrates the symmetry of rectangles:
Sketchpad Courseware Template - Demonstrating Rectangular Axisymmetric Example
In the above courseware, the demonstration takes the long center line of the rectangle as the axis of symmetry, and when half of the rectangle is folded, it will completely coincide with the other half. After clicking the "Axis Symmetry 1" button, and then clicking the "Demo" button, the process of folding half of the rectangle can be automatically demonstrated. In addition, the shape of the rectangle can also be controlled, and the values of parameters a and b can be adjusted to change.
Geometry Sketchpad Courseware Template - Demonstrates a Second Axisymmetric Example of a Rectangle
In the above courseware, the demonstration takes the wide midline of the rectangle as the axis of symmetry, and when half of the rectangle is folded, it will completely coincide with the other half. After clicking the "Axis Symmetry 2" button, and then clicking the "Demo" button, the process of folding half of the rectangle can be automatically demonstrated. As above, the shape of the rectangle can also be controlled by adjusting the values of parameters a and b to change.
Geometry Sketchpad Courseware Template - Demonstrating Rectangular Centrosymmetric Example
In the above courseware, the demonstration takes the intersection of the diagonals of the rectangle as the center of symmetry, and the rectangle is rotated 180 degrees, which will coincide with the original figure. After clicking the "Central Symmetry" button, then click the "Demo" button to automatically demonstrate the process of rotating the rectangle by 180 degrees. As above, the shape of the rectangle can also be controlled by adjusting the values of parameters a and b to change.
With this courseware, it can be used to dynamically demonstrate the symmetry of a rectangle to students, so as to demonstrate the axisymmetric and centrosymmetric properties of a rectangle. More math courseware templates can be downloaded for free on the Chinese official website of Geometric Sketchpad.
The above tutorial is referenced from: http://www.jihehuaban.com.cn/jichuji/juxing-duichen.html