Information On Today’s Lesson: Students in class stated they were familiar with finding area. Therefore, we reviewed how to use area (length x width) to find the surface area of a rectangular prism. The formula for surface area was not given to them explicitly, as students were asked to apply their previous knowledge. Students stated they were not familiar with finding the volume of a three-dimensional shape. Therefore the formula was given (length x width x height) to find volume. A student also volunteered to explain to the class why this formula finds the volume of a rectangular prism.

Monday, April 18, 2016  Math Journal  Pencil Please have only these two items on your desk this morning. You’ll need the space! Tonight’s Homework: Homework Please take one from the homework bin under the triangle poster!

Warm-Up: Please write in your math journals SIMPLE INTEREST Interest is a charge or fee for borrowing money. Interest can also be paid to you on money in your bank account. The money borrowed or the amount in your account is called the principal. (In decimal form!) Formula for calculating simple interest: I = P R T Interest = (Principal)(Rate/Percent)(Time)

Cross Sections and Volume A cross section of a three-dimensional solid is the figure obtained when the solid is intersected or “sliced” by a plane. A three-dimensional solid is an object that has length, width, and height. A plane is an object that has only length and width, like a flat sheet of paper. Today we will investigate the shapes that can be created by slicing various types of solids.

Vocabulary

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Your turn! Using the clay, make a rectangular prism or cube. Try to have each person in your team make a slightly different prism.

Slicing Your Prism Use your string to slice the rectangular prism by holding it tightly and pulling it through the solid. 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?

Slicing Your Prism Before making a new slice, reshape your prism. Which of the following shapes can you make by slicing your prism in different ways? Triangle Square Rectangle Trapezoid Parallelogram Pentagon Hexagon Octagon Circle

Create a Rectangular Pyramid! Now make a rectangular pyramid. Again, use your string as you did earlier to slice the pyramid. Place the newly created face that is made by the slice and came from the inside of the pyramid on your paper and trace the resulting shape. What is the name of your shape? What other shapes can you make by slicing your pyramid in different ways? What shapes are impossible to make?