Number PatternsPythagorasMedium
Bhaskara's "Behold!"
Four triangles and a tilted square prove Pythagoras at a glance.
Worked demonstration
Bhaskara's "Behold!" proof arranges four right triangles with legs 9 and 15 around a tilted central square. What is the AREA of that central square?
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Why it works
Four right triangles (legs a, b) frame a central square of side (b − a); the areas combine to c² = a² + b².
Background & Explore Further
Bhaskara II (1114–1185) gave this elegant dissection proof; the famous one-word 'Behold!' is part legend. Explore his deeper work — the chakravala method for Pell's equation.