At a certain time of day, a person 6 feet tall casts a 4-foot shadow. how long is the shadow cast by a 21-foot tree at the same time?
Because the shadows are being cast at the same time of day, they have the same proportions. (4*21)/6=the length of the shadow of the tree =14ft
Answer: 14ft
Explanation: here we may assume a linear relationship.
Where S, the shadow, is equivalent to H, the height.
and the relation is S = KH
where K is a constant.
So if a person 6 feet tall casts a 4-foot shadow, we have:
4 = K6
now we need to isolate K by dividing both sides by 6.
K = 4/6 = 2/3
Now that we know the value of K, if we want to find the shadow casted by a 21 ft tree, we need to solve:
S = (2/3)21 = 2(21/3) = 2*7 = 14
So the shadow casted is of 14ft