A6 ft tall tent standing next to a cardboard box casts a 15 ft shadow. if the cardboard box casts a shadow that is 6 ft long then how tall is it, and explain

What we know is that a 6 foot tall tent casts a 15 foot shadow. Lets represent that given this way: 6 = 15
So, the unknown (y), or what we want to know, is how tall the cardboard box if it has a 6 foot long shadow (noticeably the same height as the tent):
y = 6

6 = 15
y = 6

(6 x 6) / 15 = y
36 / 15 = y
2.4 = y

The height of the cardboard box is 2.4 feet.