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Brahmagupta's Formula

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Visit this site: http://jwilson.coe.uga.edu/emt725/brahmagupta/brahmagupta.html

Author:Jim Wilson, Dept. of Mathematics Education, Univ. of Georgia
Description: Problem: Develop a proof for Brahmagupta's Formula, which provides the area A of a cyclic quadrilateral (i.e., a simple quadrilateral inscribed in a circle) with sides of length a, b, c, and d as A = sqrt((s-a)(s-b)(s-c)(s-d)) where s is the semiperimeter (a+b+c+d)/2. There are alternative approaches to this proof. The one outlined here is intuitive and elementary; a more elegant approach is available using trigonometry. From a course on Problem Solving in Mathematics.

Levels: College
Languages: English
Resource Types: Course Notes
Math Topics: Conic Sections and Circles, Triangles and Other Polygons, Trigonometry

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