1. Given three point A,B,and C, Draw a line AC in the point Y such that AX=XY=YB.

GSP file is Here.

2. What is the minimum pass of AB? CD?

GSP file is Here.

3. Construct a quadrangle and two diagonal lines. A diagonal divide a quadrangle two triangle. According to two diagonals we have four triangles. Construct orthocenters of each triangles, and second quadrangle having vertexes of the orthocenters .

Here is GSP script of Orthocenter .

4.Find some rerationship between the two quadrangles.(E.g., are they cogruent ? similar? have same area ? ratio of perimeter?) Prove whatever you find.

5. The window's design. How construct below design ?

How construct this?