Lesson 9.2.2 – Teacher Notes Standard: 7.G.A.3 Describe the two-dimensional figures that result from slicing three-dimensional figures, as in plane sections of right rectangular prisms and right rectangular pyramids. Full mastery can be expected by the end of the chapter. Lesson Focus: The focus of the lesson is for students to understand the two-dimensional figure that results from a cross section. This lesson will assist students in the next lesson when they must deconstruct three-dimensional figures. (9-61) I can name the shape of the cross sections in a three-dimensional figure. Calculator: Yes Literacy/Teaching Strategy: Teammates Consult (9-61); Think-Ink-Pair-Share (Closure)

Bell Work

A cross section of a three-dimensional solid (an object that has length, width, and height) is the figure obtained when the solid is intersected or “sliced” by a plane (an object that has only length and width, like a flat sheet of paper).  Today you will investigate the shapes that can be created by slicing various types of solids. https://www.khanacademy.org/math/geometry/basic- geometry/cross-sections/v/ways-to-cut-a-cube https://www.khanacademy.org/math/geometry/basic-geometry/cross- sections/v/vertical-slice-of-rectangular-pyramid

Day 2 https://www.youtube.com/watch?v=Rc8X1_1901Q https://vimeo.com/82400980 Day 4 https://www.youtube.com/watch?v=DkvdMkR8V8g

9-61. Using clay, make a rectangular prism or cube 9-61. Using clay, make a rectangular prism or cube.  An example is shown below right.  Each person in your team should make a slightly different prism. a. Use your string to slice the rectangular prism by holding it tightly and pulling it through the solid.  An example is shown at right.  Place the newly created face made by the slice that came from the inside of the rectangular prism on your paper and trace the resulting shape.  What is the name of your shape? https://www.youtube.com/watch?v=Rc8X1_1901Q

b. Which of the following shapes can you make by slicing your prism in different ways?  Before making a new slice, reshape your prism. Triangle Square Rectangle  Trapezoid  Parallelogram    Pentagon    Hexagon  Octagon  Circle  c. Even though each team member had a slightly different rectangular prism, were you able to create the same cross sections?  Were there any shapes that one team member could create and another could not?  https://vimeo.com/82400980

Practice Find the volume of each figure below: a. b. c.