Unit 5 - Lesson 18 - Grade 8: Illustrative Mathematics

Which of these statements are true? Select all that apply.

• A. If a is tripled, m is tripled.
• B. If a, b, and c are all tripled, then m is tripled.
• C. If a is tripled, n is tripled.
• D. If a, b, and c are all tripled, then n is tripled.

Create a true statement of your own about one of the equations.

Clare sketches a rectangular prism with a height of 11 and a square base and labels the edges of the base s. She asks Han what he thinks will happen to the volume of the rectangular prism if shetriples s.Han says the volume will be 9 times bigger. Is he right? Explain or show your reasoning.

Write an equation that expresses the relationship between V and r. Use 3.14 as an approximation for π.

Predict what happens to the volume if you triple the value of r.

What happens to the volume if you triple r? Where do you see this in the graph? How can you see it algebraically?

Write an equation that expresses the relationship between the volume, height, and radius of this cylinder using c and V.

If the value of c is halved, what must happen to the value of the volume V?