A triangle has sides with lengths of 8, 4, and 7. What is the radius of the triangles inscribed circle?

1 Answer
Oscar L.
Feb 28, 2016

r = #\sqrt{3135}/38#

About 1.47.

Explanation:

Let s be half the perimeter of the triancle with sides a, b, c. Then the radius of the inscribed circle is given by:

r=#\sqrt{(s-a)(s-b)(s-c)/s}#

See here:

http://www.efunda.com/math/areas/circleinscribetrianglegen.cfm

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