About 2,600 years ago, the Greek mathematician Thales found the height of an Egyptian pyramid without climbing it. He simply placed a stick in the ground and used the ratio of the shadow lengths. Try the same method yourself.
Principle: At the same time of day, sunlight arrives in parallel rays. That makes the triangle formed by the stick and its shadow and the triangle formed by the building and its shadow similar triangles. So the proportion "stick height : stick shadow = building height : building shadow" always holds.
☀️ Sun elevation (angle)40°
Stick height
1.5 m
Stick shadow length
-
Building shadow length
-
Building height
❓
Building height = m
Set up the proportion 1.5 : stick shadow = building height : building shadow, then calculate building height = 1.5 × (building shadow ÷ stick shadow).