The circumference of a steering wheel of a car is 20 inches. What is the radius of the steering wheel?
40 in.
20 in
100 in.
10 in.

10π or 3.18

Step 1: Write equation

To solve for the radius, we must first find the equation. We will use the formula for a circumference. The circumference is equal to 2 times pi (π) times the radius. Let’s write the equation now.

C=2πr

Step 2: Substitute information

Before we find the radius, we must first substitute the information provided to us. In this case, we can substitute c for 20, as that is the circumference.

C=2πr
20= 2πr

Step 3: Solve for the radius

Now that we have steps one and two done, we can solve for the radius. Let’s start by rewriting the equation.

20= 2πr

Great! Now let’s get rid of the constant on the right side. Let’s divide each term by 2.

20= 2πr
10= πr

Now let’s move the pi side to the left. Divide each term by pi to do so.

10= πr
10π= r

This is your answer! If desired, you could divide the term by pi to get the proper answer of 3.18. Since this is not an option provided, I will leave the answer as 10π, assuming that the teacher would like you to leave the pi symbol.