thursday, january 19 th
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Thursday, January 19th • Please complete the warm up and write down
your homework• Please have your own angle matches out
Warm Up1. Simplify
2. Write an expression for 2 times three more than twice a number
250 7 4 6
Corny Joke of the Day
Why did Wesley bring a ladder to
school?
Because he wanted to get to
high school
Angle Match• Using the cards you made last
night…..• Switch your cards with the person
who is sitting to your left • Then, try to categorize their cards
into the four main angle types!
Symmetry
OUR MISSION
Learn to identify line symmetry.
Making Unusual ShapesFold your piece of paper in half Cut an unusual shape from it Unfold it What do you notice?The parts of the shape What does the folded line
represent?
A figure has line symmetry if it can be folded or reflected so that the two parts of the figure match, or are congruent. The line of reflection is called the line of symmetry.
Part 1 Lines of symmetry in regular polygons
Regular polygons: All side lengths and angles are
congruent
Can you find the rule?Find the number of lines of
symmetry in each shape and fill out the chart.Shape Number of Sides Lines of
symmetryTriangle
Square
Pentagon
Hexagon
Octagon
4 lines of symmetry
DiscoveryFor a regular
polygon the lines of symmetry is the same as
the number of sides!
Fun FactA dodecagon is a 12-
sided regular polygon. This means that it has
___________lines of symmetry!
Part 2 Determining if the lines given are the lines
of symmetry
Determine whether each dashed line appears to be a line of symmetry.
The two parts of the figure appear to match exactly when folded or reflected across the line.
The line appears to be a line of symmetry.
#1
Determine whether each dashed line appears to be a line of symmetry.
The two parts of the figure do not appear congruent.
The line does not appear to be a line of symmetry.
#2
Determine whether each dashed line appears to be a line of symmetry.
The two parts of the figure do not appear congruent.
The line does not appear to be a line of symmetry.
#3
Determine whether each dashed line appears to be a line of symmetry.
The two parts of the figure appear to match exactly when folded or reflected across the line.
The line appears to be a line of symmetry.
#4
Group DiscussionHow many lines of symmetry does the following shape have?
NOT EVERY SHAPE HAS A
LINE OF SYMMETRY
1 line of symmetry
Is there a line of symmetry. If so, how many?
Smile Symmetry
LOGO SYMMETRY
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