Intercept Theorem Calculator

Calculate with the intercept theorem to set the height and shadow length of two objects in relation. The intercept theorem states, among other things, that the ratio of height and length of the shadow cast by different objects standing next to each other is the same. So if you know three of the values, you can calculate the fourth.

Height 1:
Length 1:
Height 2:
Length 2:

Please enter three values, the fourth value will be calculated. Ratio height 1 / length 1 = height 2 / length 2

Example: Thales of Miletus used the intercept theorem to determine the height of the Great Pyramid of Giza. He stuck a stick 1.63 meters high (the exact historical values are not known) into the ground and measured a shadow length of 2 meters. The shadow of the pyramid, from the top projected on the ground to the top of the shadow, was 180 meters long at the same time on the same day. Therefore, the height of the pyramid at that time was 146.7 meters.
Due to erosion, the pyramid is now only 139 meters high.

Physics commonly uses SI units. Here is a calculator to convert units.