? Name 13.6 Essential Question Find and raw Lines of Symmetry How do you find lines of symmetry? Geometry and Measurement 4.6. MTHEMTIL PROESSES 4.1., 4.1.F, 4.1.G Unlock the Problem How many lines of symmetry does each polygon have? ctivity 1 Find lines of symmetry. Materials isometric and square dot paper straightedge STEP 1 raw a triangle like the one shown, so all sides have equal length. STEP 2 Fold the triangle in different ways to test for line symmetry. raw along the fold lines that are lines of symmetry. Is there a line of symmetry if you fold the paper horizontally? STEP 3 Repeat the steps for each polygon shown. omplete the table. Polygon Number of Sides 3 Triangle Square Parallelogram Rhombus Trapezoid Hexagon Number of Lines of Symmetry 3 Houghton Mifflin Harcourt Publishing ompany In a regular polygon, all sides are of equal length and all angles are equal. What do you notice about the number of lines of symmetry in regular polygons? Math Talk Mathematical Processes How many lines of symmetry does a circle have? Explain. Module 13 479
ctivity 2 Make designs that have line symmetry. Materials pattern blocks Make a design by using more than one pattern block. Record your design. raw the line or lines of symmetry. ERROR lert To avoid errors, you may use a mirror to check for line symmetry. Make a design with 2 lines of symmetry. Make a design with 1 line of symmetry. Make a design with more than 2 lines of symmetry. Make a design with zero lines of symmetry. Share and Show 1. The figure at the right has line symmetry. raw the 2 lines of symmetry. 480 Houghton Mifflin Harcourt Publishing ompany
Name Tell whether the figure appears to have zero lines, 1 line, or more than 1 line of symmetry. Write zero, 1, or more than 1. 2. 3. 4. 5. Problem Solving Use the chart for 6 8. Math Talk Mathematical Processes Explain how you can find lines of symmetry for a figure. 6. Which letters appear to have only 1 line of symmetry? Houghton Mifflin Harcourt Publishing ompany Image redits: (l) Siede Preis/Photodisc/Getty Images: (r) harles Smith/orbis 7. Which letters appear to have zero lines of symmetry? 8. The letter has horizontal symmetry. The letter has vertical symmetry. Which letters appear to have both horizontal and vertical symmetry? 9. Justify Sense or Nonsense? Jeff says that the figure has only 2 lines of symmetry. oes his statement make sense? Explain. E H I J K L S T U V W 10. ommunicate Multi-Step raw a figure that has at least 2 lines of symmetry. Then write instructions that explain how to find the lines of symmetry. Module 13 Lesson 6 481
aily ssessment Task Mathematical Processes Fill in the bubble completely to show your answer. 11. How many lines of symmetry does the shell have? 0 2 3 1 12. Which shows all the lines of symmetry for the figure below? 13. Which describes the figure? zero lines of symmetry more than 2 lines of symmetry 2 lines of symmetry 1 line of symmetry TEXS Test Prep 14. How many lines of symmetry does the figure to the right have? 10 5 3 0 482 Houghton Mifflin Harcourt Publishing ompany
Homework and Practice Name Geometry and Measurement 4.6. MTHEMTIL PROESSES 4.1., 4.1.F, 4.1.G 13.6 Find and raw Lines of Symmetry Tell whether the shape appears to have zero lines, 1 line, or more than 1 line of symmetry. Write zero, 1, or more than 1. 1. 2. 3. 4. Problem Solving Use the poster for 5 6. 5. Erica is cutting out letters for a science poster. Which letters on Erica s poster appear to have only 1 line of symmetry? 6. Which letters on Erica s poster appear to have zero lines of symmetry? Houghton Mifflin Harcourt Publishing ompany 7. Write your own poster words. Include letters that have zero, one, and two lines of symmetry. Then draw the lines of symmetry. Module 13 Lesson 6 483
Lesson heck TEXS Test Prep Fill in the bubble completely to show your answer. 8. How many lines of symmetry does the jar have? 9. Which describes this figure? zero lines of symmetry 0 2 1 3 1 line of symmetry 2 lines of symmetry more than 2 lines of symmetry 10. Which shows all the lines of symmetry for the figure? 11. How many lines of symmetry does the figure have? 3 2 1 0 12. Multi-Step Which statement about the number of lines of symmetry is true? 13. Multi-Step Lance drew this figure with two lines of symmetry. Which statement is true about the number of lines of symmetry? They are greater than the number of sides. They are the same as the number of sides. 484 They are less than the number of angles. They are the same as the number of sides. They are greater than the number of angles. They are greater than the number of sides. They are less than the number of pairs of sides of equal length. They are the same as the number of pairs of sides of equal length. Houghton Mifflin Harcourt Publishing ompany
Name Module 13 ssessment Vocabulary hoose the best term from the box to complete the sentence. 1. is part of a line between two endpoints. (p. 449) 2. forms a square corner. (p. 450) 3. n is greater than a right angle and less than a straight angle. (p. 450) Vocabulary acute angle line segment obtuse angle ray right angle straight angle 4. The two-dimensional figure that has one endpoint is a. (p. 449) 5. n angle that forms a line is called a. (p. 450) oncepts and Skills Use Figure for 6 11. q TEKS 4.6. 6. Name a ray. 7. Name an acute angle. E 8. Name a point. 9. Name a line segment. G F 10. Name a pair of perpendicular lines. 11. Name an obtuse angle. Figure lassify each triangle. Write acute, right or obtuse. q TEKS 4.6. Houghton Mifflin Harcourt Publishing ompany 12. 13. 14. Module 13 485
Fill in the bubble completely to show your answer. TEXS Test Prep 15. Which describes the figure? q TEKS 4.6. zero lines of symmetry 1 line of symmetry 2 lines of symmetry more than 2 lines of symmetry 16. Which figure has 2 pairs of sides that appear to be parallel? q TEKS 4.6. 17. Which quadrilateral can have 2 pairs of parallel sides, all sides with equal length, and no right angles? q TEKS 4.6. square rhombus rectangle trapezoid 18. Which names the figure correctly? q TEKS 4.6. F E line FE ray FE angle FE 486 ray EF Houghton Mifflin Harcourt Publishing ompany