In this lesson, students use the formula for the volume of a sphere to solve various problems. The Warm-up begins with an opportunity to analyze common errors that people make when using this formula.

The main activity in this lesson is an Information Gap. In it, students must reason about a cone and sphere with matching dimensions and ask precise questions to get the information they need to solve the problem (MP6).

The second and last activities in the lesson are optional. In the second activity, students use the structure of an equation to find the radius of a sphere when they know its volume. Consider using this activity if students would benefit from additional practice working with the volume of a sphere before the Information Gap. In the last activity, they have opportunities to practice using all of the new volume formulas they have learned in this unit. Use this activity if time allows and students would benefit from extra practice working with volume formulas and equations involving .

Display the poster with the volume formulas from this unit throughout the lesson for students to refer to.