Concept
Method of exhaustion
Pinning a quantity down by bounding it above and below with pieces that can be made as small as needed.
Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.
A circle unrolled into a triangle
Take a disc apart into rings, straighten each one, and stack them. The result is a triangle whose base is the circumference and whose height is the radius — and its area is the disc's.
The sum that fits in one square
Half, then a quarter, then an eighth, forever. Adding infinitely many things sounds like it should give infinity, and the picture that says otherwise is a square with a corner left uncut.
Named alongside it
The objects these essays reach for when they reach for this one.
DissectionLimitArchimedesAreaCircle areaConvergenceConvergence rateGeometric seriesHarmonic seriesPiPower seriesReal numbers