Mathematics
Similar Triangles and Their Applications
Quick fact
The Greek philosopher Thales measured the height of the Great Pyramid of Giza by comparing its shadow with the shadow of a stick, using the property of similar triangles over 2,500 years ago.
Why this is interesting
You can measure the height of a tree without climbing it—just by measuring a shadow and using a stick. How is that possible? The answer lies in a simple yet powerful idea: similar triangles.