2 Objective Plane s The reasoning skills that students develop at this age allow them to explore more complex geometric problems and properties. They should develop more precise ways to describe and classify shapes, with an emphasis on using the specialized vocabulary associated with the geometric attributes and properties. The words parallel, perpendicular, and vertex should be introduced and used repeatedly in context when discussing two-dimensional shapes. Common Core State Standards 4.G.2 Talk About It Discuss the Try It! activity. Draw a triangle, circle, square, and rectangle on the board. Point to each shape. Ask: How many vertices does this shape have? How many sides? How many parallel sides? What is the name of this shape? Display one Attribute Block. Ask: What shape is this? How can you tell? Encourage students to describe the shape using the correct geometric vocabulary. Then challenge students to name correct shapes by giving them clues using attributes. Solve It With students, reread the problem. Have students draw the shape Nick and his friends were supposed to make. Instruct students to label each side and vertex and write a sentence telling how they knew which shape was being described. (square or rhombus) More Ideas For other ways to teach about identifying and comparing plane shapes Name a two-dimensional shape, then have students build it on a Geoboard. Instruct students to compare results with a partner and explain the attributes of the shape. Point out that while the Geoboard shapes may vary in size, side length, and position, they should all have the same number of sides, vertices, and so on. Play What Am I? by telling riddles about two-dimensional shapes. For example, say: I have 3 sides and 3 vertices. None of my sides are parallel. Ask: What shape am I? Have students hold up a Pattern Block of that shape to show their answer. Formative Assessment Have students try the following problem. Which shape has parallel lines? 132 A. B. C. D.
Try It! 20 minutes Pairs Here is a problem about identifying and comparing plane shapes. Mr. Roberts asks Nick and his friends to help him get the playground ready for a game the class will play during recess. He asks the students to use chalk to make a large shape on the pavement. The shape should have two sets of parallel sides that are all the same length. It should have four corners. How can the boys figure out what shape Mr. Roberts is asking them to make? Introduce the problem. Then have students do the activity to solve the problem. Distribute materials to students. Introduce and define the terms vertex (the point where two sides join), perpendicular (lines that intersect and form only right angles), and parallel (lines that never cross and stay the same distance apart at all points) for students. Materials Attribute Blocks (1 circle, 1 square, 1 rectangle, and 1 triangle per student) Plane s Recording Sheet (BLM 10; 1 per student) pencils (1 per student) 1. Instruct students to select a circle, square, rectangle, and triangle block, and discuss similarities and differences between the shapes. Have students complete the first and second rows of the Plane s Recording Sheet. 2. Explain that the plural of vertex is vertices. Instruct students to write the number of sides in the third row and the number of vertices in the fourth row for each shape. 3. Have students look for parallel sides in the shapes. Instruct students to write the number of parallel sides in the fifth row for each shape. The geometric terms introduced in this lesson may be difficult to remember for some students. If so, draw a square or rectangle on the board. Write the terms side, vertex, perpendicular lines, and parallel lines on the board next to the shape, and draw arrows to parts of the shape to indicate examples of each term. Emphasize the parallel and perpendicular lines on the shape using thicker lines. Have students use masking tape to label the sides, vertices, perpendicular lines, and parallel lines on the blocks. 133
Lesson 2 Name Answer Key Choose an Attribute Block that matches each shape. Name the shape. Fill in the blanks with the correct numbers. (Check students work.) 1. 2. 3. square circle rectangle 4 0 4 4 0 4 2 0 2 Using Attribute Blocks, select each shape named. Then complete the table. Name of Sketch of Vertices Parallel 4. triangle 3 3 0 5. hexagon 6 6 3 Sketch each shape described. Name the shape. 6. 4 4 Vertices 2 Parallel 7. 0 0 Vertices 0 Parallel 8. 3 3 Vertices 0 Parallel rectangle or ; square ; circle ; triangle 134 Download student pages at hand2mind.com/hosstudent.
Answer Name Key Challenge! Name a three-sided figure and explain why it cannot have any parallel sides. Draw a picture to help. Challenge: (Sample) A triangle has three sides. At each vertex, two of the three sides meet, so each side touches the other two sides. Download student pages at hand2mind.com/hosstudent. 135
Lesson 2 Name Choose an Attribute Block that matches each shape. Name the shape. Fill in the blanks with the correct numbers. 1. 2. 3. Using Attribute Blocks, select each shape named. Then complete the table. Name of Sketch of Vertices Parallel 4. triangle 5. hexagon Sketch each shape described. Name the shape. 6. 4 4 Vertices 2 Parallel 7. 0 0 Vertices 0 Parallel 8. 3 3 Vertices 0 Parallel 134 www.hand2mind.com
Name Challenge! Name a three-sided figure and explain why it cannot have any parallel sides. Draw a picture to help. www.hand2mind.com 135
Name BLM 10 Plane s Recording Sheet Name of Sketch of Number of Number of Vertices Number of Parallel BLM 10 Plane s Recording Sheet 157