Mark has model wheels with a diameter of 6 inches. If the actual wheel radius is 2.25 feet, will they be in proportion with his model?

Question

Mark has model wheels with a diameter of 6 inches. If the actual wheel radius is 2.25 feet, will they be in proportion with his model?

Answer 1

Yes they will.  When you have a proportion, there is a scale factor associated with it.

 

First, we need to get everything in terms of radius.  If the diameter of the model wheel is 6 inches, then its radius is 3 inches.

 

Next, we convert the inches to feet.

 

3 inches = 3/12 foot = 1/4 foot

 

 

Finally, divide the radius of the actual wheel by the radius of the model wheel.

 

2.25 ft / (1/4 ft) = 9

 

 

This means that the scale factor of the model wheel to the actual wheel is 9.