If a statue that is 12 ft tall casts a shadow that is 15 ft long. find the length of the shadow that is 8 ft cardboard box casts

So ratios.

If you don't know what a ratio is, look it up.

the ratio for the 1st one is 15 (shadow) : 12 (actual height)

the next would be x:8

so 12/8 is 1.5

then you divide 15 by 1.5 to get 10

so the shadow should be 10ft long.