standard_description: Recognize a line of symmetry for a two-dimensional figure as a line across the figure such that the figure can be folded along the line into matching parts. Identify line-symmetric figures and draw lines of symmetry.
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: yes