How do you find a scale factor of an image?

Here is an example:

If the size of the hair piece(image) is 10 inches from head to tail, what is th scale factor?

Here is another:

The measurement on a real grasshopper- Lower Hind Leg 1 1/8inches

Ground to the Head 7/8 inches

(1)Using the scale factor, what is the size of the lower hind leg?

(2)Using the scale factor, what is the size of the ground to the head?

How do you find a scale factor of an image?

You're not providing enough information. Generally, the scale factor is a ratio like 1:48 or 1:100,000 that is an indication of the magnification of the image. You would use that ratio to multiply by the size of the image to determine the real size.