The composition of two reflections
about parallel lines that are 5 units
apart is a translation of
magnitude [?]

The shadow of the dog is 7 feet long.

Step-by-step explanation:

Given:

Height of the scarecrow is 6-foot-tall and it casts a shadow that is 21 feet. Height of the dog is 2 feet tall.

So, here we need to find the dog's shadow.

Let the shadow of dog be

So, if the 6-foot-tall scarecrow casts shadow of 21 feet, then the 2 feet tall dog casts shadow of .

According to question:

By cross multiplication:

Now, dividing by  6 on both sides we get:

Therefore, the shadow of the dog is 7 feet long.