standard_description: Verify experimentally the properties of dilations given by a center and a scale factor:
- A dilation takes a line not passing through the center of the dilation to a parallel line, and leaves a line passing through the center unchanged.
- The dilation of a line segment is longer or shorter in the ratio given by the scale factor.
problem_activity: Task
Mr. Watkins asked his students to draw a line of symmetry for a circle
with center $O$ pictured below:
[IMG]
Lisa drew the picture below. Is Lisa correct?
[IMG]
Brad drew the picture below. Is Brad's picture correct?
[IMG]
How many lines of symmetry does a circle have? Explain.
Explain why  each line of symmetry divides the circle in half.
Explain why each line of symmetry for the circle must go through the center.


aligns: no