home construction Thinking
Euclid
Tech

foundation
intermediate
advanced
Euclid's Elements

euclidBook 1: The 48 Propositions
37 Triangles which are on the same base and in the same parallels are equal to one another.
Let ABC, DBC be triangles on the same base BC, and in the same parallels AD, BC. Please enable Java for an interactive construction (with Cinderella).