Lesson objective: Fluently find the exact and approximate volumes of cones.

This lesson helps to build fluency with using the formula for finding the volume of cones. Three-dimensional modeling is used here because it supports the abstract nature of using formulas to find volumes and their component parts. This work develops students' understanding that the volume of a cone takes into account the area of the base and the height of the cylinder it "sits inside of."

Students engage in Mathematical Practice 2 (Reason abstractly and quantitatively) as they dissect the visual representation of each cone to determine which components are given, as they determine how each component is to be incorporated into the formula for finding volume, as they decide how to appropriately apply mathematical reasoning to arrive at an answer, and as they describe what the answer actually means.

**Key vocabulary:**

- cylinder
- cone
- diameter
- height
- radius
- volume