Theodorus (mathematician)

Theodorus was an ancient Greek mathematician active around the 5th century BCE, known for his work in geometry. He is especially famous for proving that the square roots of numbers like 3, 5, and 7 are irrational—that is, cannot be expressed exactly as fractions. He also studied right triangles and believed to have developed methods for constructing geometric figures. While little is documented about his entire body of work, his contributions helped advance understanding of irrational numbers and geometric principles in early mathematics.