#### Transcript Classifying Triangles by Angles - fourthgradeteam2012-2013

```Classifying
Triangles
Classifying Triangles by
Angles
One way to classify triangles is by their
angles…
Acute Triangles
76°
37°
67°
_________ triangle: three ________ that
measure less than _______ degrees.
Obtuse Triangles
142°
13
°
25
°
･ __________ triangle: one ________
that measures greater than _____
degrees. There can only be one
________ angle in any __________.
Right Triangles
42
°
48
°
90
°
･ __________
triangle: one
_______ that
measures _______
degrees. **A right
triangle can either
be scalene or
isosceles but never
equilateral.
Classifying Triangles by Sides
Another way to classify triangles
is by their sides…
Isosceles Triangle
･ ____________
triangle: A triangle with
two ________ sides and
two equal
____________.
Equilateral Triangle
･ __________ triangle: A triangle with
three ________ sides and three
_________ angles. The slash marks
indicate equal measure.
Scalene Triangle
･ ___________ triangle: A
triangle with three sides that
are not _______ and three
________ that are not
________.
Question 1
• Is it possible to make a three-sided
polygon that is not a triangle?
Question 2
• Is it possible for a triangle to have
two right angles?
Question 3
• How many different right triangles
can be made on the geoboards?
Question 4
• How many different types of angles
can you find?
Wednesday
October 3, 2012
Any 4 sided, closed figure
Student Activity
you
• Draw a VennDiagram on your
whiteboard.
• Using the label cards, sort your
Student Activity 2
• Create the VennDiagrams based on the
worksheet “Unknown Labels”
• Figure out which label would fit each
ring for each VennDiagram.
Response Questions
• What attributes were you looking for
• What were some categories that were
easy to group? Harder to group?
Thursday
October 4, 2012
Seth wants to make the mask of his favorite super
hero to wear to his his birthday party. He tore last
years mask and only has half of it. He’s hoping to
use that half as a pattern for making his new
Seth create a new mask using the half he has from
last year.
Symmetry
• The "Line of Symmetry" is the
imaginary line where you could fold the
image and have both halves match
exactly.
• Trace a blue rhombus in your math journal
– What two pattern blocks could be placed
inside of it so that there are 2 congruent
parts?
– This shows the line of symmetry for the
rhombus
• Trace the hexagon in your math journal
– What two pattern blocks could be placed
inside of it so that there are 2 congruent
parts?
– This shows the line of symmetry for the
rhombus
• Repeat with the trapezoid.
Student Activity 1
• Students should be in pairs
• Have each student fold a piece of paper
in half and draw a line down the middle.
Then place pattern blocks along one
side of the line and trace them.
• The partner should match up the
shapes that belong on the other line of
symmetry
Student Activity 1 Questions
• How did you know what you filled in on
your partner’s paper would make a
symmetrical image?
• What is a mirror image?
• What mistakes (if any) did you find?
Student Activity 2
• Revisit the Super Hero Mask problem.
along the center and placing pattern
blocks along the fold.
• Unfold the paper and use pattern blocks
to complete the other half.
Student Activity 2 Questions
symmetrical?
symmetry?
• How did you use symmetry to create a
mask when you only knew what half
looked like?
Friday
October 5, 2012
Student Activity- Classroom
Quilt
• You will design 2 identical squares for
our quilt. The design is up to you, but it
must meet the following criteria:
– You may use up to 10 pattern blocks to
– Your square must only have 1 line of
symmetry
– Your design must fit inside the patchwork
square provided.
• After completing your design on one
square, you must recreate the exact
design on the second.
– On one of your squares, use a marker or
pencil to draw the line of symmetry. On the
back of the square explain the strategy you