2.03 Scale Drawings using the Parallel Method
Creating a scale drawing using the parallel method:
- Draw a ray
beginning at the center through each vertex of the figure. - Dilate one vertex along the appropriate ray by the scale factor. For example for a scale factor r = 1/2, find the midpoint between the center and vertex A.
- Construct a line parallel
to AC going through the vertex from step 2. - Mark the point of intersection
of this line and the ray going through point C. - Construct a line parallel to AB going through the vertex from step 2.
- Mark the point of intersect of intersection of this line and the ray going through point B.
- Use the polygon tool
to join the vertices in the way they are joined in the original figure.
Create a scale drawing of triangle ABC about center D and scale factor r = 1/2.
How can we verify that the scale drawing has been correctly constructed? Describe below and then do this.
Use the figure below to respond to the tasks that follow.
What type of angle pair are angles FEG and CAB?
Explain why angles are preserved in scale drawings.