Classifying Triangles

Classifying Triangles by Classifying Triangles by SidesSides

Another way to classify triangles is by their sides…

Equilateral Triangle

･ __________ triangle: A triangle with three ________ sides and three _________ angles. The slash marks indicate equal measure.

Isosceles Triangle

･ ____________ triangle: A triangle with two ________ sides and two equal ____________.

Scalene Triangle

･ ___________ triangle: A triangle with three sides that are not _______ and three ________ that are not ________.

Classifying Triangles by Classifying Triangles by AnglesAngles

One way to classify triangles is by their angles…

Right Triangles･ __________ triangle:

one _______ that measures _______ degrees. **A right triangle can either be scalene or isosceles but never equilateral.90°48°

42°

Obtuse Triangles

25°

142°13°

･ __________ triangle: one ________ that measures greater than _____ degrees. There can only be one ________ angle in any __________.

Acute Triangles

37° 67°

76°

_________ triangle: three ________ that measure less than _______ degrees.

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

Quadrilaterals

Any 4 sided, closed figure

Student Activity

• Place your 16 quadrilaterals in front of you

• Draw a VennDiagram on your whiteboard.

• Using the label cards, sort your quadrilaterals on the VennDiagram

Student Activity 2

• Create the VennDiagrams based on the worksheet “Unknown Labels”

• Figure out which label would fit each ring for each VennDiagram.

• Explain your reasoning.

Response Questions

• What attributes were you looking for when grouping the quadrilaterals?

• 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 mask. Use what you know about symmetry to help 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.

• Create your own mask by folding paper 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

• How do you know that your mask is symmetrical?

• How can you test your mask for 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

create your square– 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 used to design your square.

– Give the other square to a partner to verify the line of symmetry. Your “unmarked” square will be used to construct our Classroom Quilt.

Quilt Square Examples

Response Questions

• How do you know your square had symmetry?

• What strategies did you use to verify symmetry?