If the earth were one inch in diameter, how big would the moon be in inches

The diameter of Earth is 12742 kilometers. If the model that represents the Earth has diameter of 1 inch, then the scale is:

1 inch = 12742 kilometers

Expressing this as a ratio, it becomes 1:12742.

The diameter of the moon is 3474 kilometers. To determine the diameter of the model of the moon in inches, assign a variable that represent it.  Let it be x.

x inches  = 3474 kilometers

Expressing it as a ratio, it becomes x:3747.

To solve for the value of x, set the two ratios equal to each other. Take note that when used in equations, the ratio should be in fraction form.

`x/3747=1/12742`

Isolating the x, the equation becomes

`x=1/12742*3747`

`x=0.2726`  

Therefore, the diameter of the model of the moon is 0.2726 inch.