Help Me To:
Eligible Content M3.C.2.1.3
Help Me To:
Identify symmetrical two-dimensional shapes.
Did You Know?
A two-dimensional shape is symmetrical when one half of the figure looks like the mirror image of the other half.
Check What You Know First
Look at the figures on the grid and decide if they
are symmetrical. Write yes or no.
5) Point
Here for the answer
6) Point
Here for the answer
Key Vocabulary
Symmetry - when one half of a figure looks like the mirror image of the other half
A line of symmetry is an imaginary line that divides a figure into halves that match or two congruent parts.
Congruent - Figures that have the same size and shape.
Learn About It Now
Symmetry occurs
when one half of a figure looks like the mirror image of the other half. You can demonstrate this by folding
a
figure in half and both sides should match. The imaginary line that divides
the figure into halves that match is called
a
line of symmetry.
Look at the following example. You can fold the pentagon along its line
of symmetry. Both halves will match.
Try the following art activity to make a symmetrical figure.
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Now let’s look at the figures you identified as symmetrical or not symmetrical. In
the problems that you did,
numbers 3, 5 and 6 have a line of symmetry. If you
folded the figures in half, both sides would match. Problems
1, 2 and
4 do not have symmetry. It does not matter which way you fold the figures. No
two sides will match.
More Practice With Symmetry
Identify which picture is symmetrical. Write A or B.
Websites to Check Out For Extra Practice and Review
Click below to
see and hear a lesson on symmetry. This
lesson is a good review of the concept of symmetry. Once you have
clicked on
the site, scroll down and click on Teaching Model 15.9 symmetry. Make
sure you have turned on your speakers.
http://www.eduplace.com/math/mw/models/tm_5.html
Click below to practice making a line of symmetry on a figure.
http://www.harcourtschool.com/activity/elab2004/gr4/19.html
Click below to see and hear a lesson on symmetry. This
lesson provides excellent quizzes to test your knowledge of symmetry.
Make
sure you have turned on your speakers.
http://www.linkslearning.org/Kids/1_Math/2_Illustrated_Lessons/4_Line_Symmetry/index.html
Click below to view a unit on geometry and
shapes including a section on symmetry. To order a copy of the unit Shapes,
Shapes,
Everywhere, go to the website for contact information.
http://www.mcrel.org/PDF/Curriculum/5021CM_Shapes.pdf
Other Fun Websites on Symmetry
Click below to make a symmetrical butterfly.
http://www.smm.org/sln/tf/s/symmetry/symmetry.html
Click below to draw a symmetrical picture.
http://www.geocities.com/ptmcg/Symmetry.html
Click on the following sites from teachers network to view
symmetry in the world around us.
Site
on symmetry
http://www.teachersnetwork.org/dcs/math/symmetry/
Site
on point symmetry
http://www.teachersnetwork.org/dcs/math/symmetry/Point/
Site
on line symmetry
http://www.teachersnetwork.org/dcs/math/symmetry/Linesymmetry
Click below to learn a lot about symmetry through a slide
show with fantastic pictures. There is a challenge game for you to play.
http://www.adrianbruce.com/Symmetry/
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