2.02 Make Scale Drawings with Ratio Method - Activity
Creating a scale drawing using the ratio method:
- Draw a ray
beginning at the center through each vertex of the figure. - Dilate each 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 each vertex. - 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 whether your triangle really is a scale drawing of triangle ABC?
Finding the location of center:
- Draw a ray beginning at A through A'. Repeat for each corresponding vertex of the figure.
- Mark the point of intersection of the rays. This point is the center.
Find the location of the center.
One of the following images shows a well-scaled drawing of triangle ABC done by the ratio method; the other image is not a well-scaled drawing.
Use your tools to make the necessary measurements and show the calculations that determine which is a scale drawing and which is not.
Figure 1
Figure 2
Which image is a scale drawing?
Explain your answer above.