Once upon a time, a wise Greek man named Thales came to Egypt. Thales was good at maths. He also loved solving puzzles and finding out how things worked. One day, he visited the Great Pyramid. It was the tallest building he had ever seen. After enjoying its beauty, he wondered how tall the pyramid was. He asked the locals, but nobody knew.
Thales thought about this question day and night. One night, when he was enjoying the moonlight, he came to realize that everything has a shadow when the sun shines. An idea hit him," If I can measure(测量) the pyramid's shadow, I can figure out its height!"
So, Thales waited patiently until the sun was just right. He stood next to the pyramid and measured his own shadow. Then, he measured the pyramid's shadow. Thales was about 6 feet tall, and his shadow was 2 feet long. The ratio(比例) was 3:1. The pyramid's shadow was much longer, about 120 feet. Thales realized that the pyramid's height equals 120 multiplied by 3.
Finally, at lunchtime, Thales declared the Great Pyramid's height—____ feet. Everyone was amazed. Thales used his wisdom to solve the puzzle.