Citizen Math used to be called Mathalicious. If you have a current account on Mathalicious, you can use those credentials to log in to your Citizen Math account. Learn more here.  ## How do vehicles turn so smoothly? How do vehicles turn so smoothly? When a car makes a U-turn, the outer wheel travels farther than does the inner wheel. So why doesn’t the car feel jerky?

In this lesson, students calculate the circumferences of circles to determine how far vehicles travel during a turn and explore the engineering that allows cars to turn so smoothly.

### REAL WORLD TAKEAWAYS

• A turning radius describes the smallest circle a car can make. The smaller the radius, the tighter the turn.
• Left and right car wheels have to cover different distances – and thus rotate different numbers of times – when turning. A differential axle allows this to happen.

### MATH OBJECTIVES

• Calculate the circumference of a circle
• Model with geometry to solve real-world problems

Appropriate most times as students are developing conceptual understanding.  