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 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?