To solve this problem, you need to make a proportion in which the height of a tree (21 meters) relates to the length of its shadow (x) in the same way as a person’s height (1.75 m) relates to the length of his shadow (3 meters).
21 / x = 1.75 / 3.
We multiply the extreme terms of the proportion among ourselves.
1.75 * x = 21 * 3.
1.75 * x = 63.
x = 63 / 1.75 = 36 meters.
Answer: A tree with a height of 21 meters casts a shadow 36 meters long.
One of the components of a person's success in our time is receiving modern high-quality education, mastering the knowledge, skills and abilities necessary for life in society. A person today needs to study almost all his life, mastering everything new and new, acquiring the necessary professional qualities.