# Incircle of a triangle Calculator

## Calculates the radius and area of the incircle of a triangle given the three sides.

 side a side b side c 6digit10digit14digit18digit22digit26digit30digit34digit38digit42digit46digit50digit inradius r diameter φ incircle area Sc triangle area St area ratio Sc/St
 $\normal Incircle\ of\ a\ triangle\\(1)\ incircle\ radius:\hspace{2} r={\large\frac{\sqrt{s(s-a)(s-b)(s-c)}}{s}}\\\hspace{230} s={\large\frac{a+b+c}{2}}\\(2)\ incircle\ area:\ Sc=\pi r^2\\\vspace{5}(3)\ triangle\ area:\ St=\sqrt{s(s-a)(s-b)(s-c)}\\$

Incircle of a triangle
 [1-4] /4 Disp-Num5103050100200
[1]  2018/05/30 03:15   Female / 30 years old level / An engineer / Useful /
Purpose of use
Calculating useful area of patio shade.
Comment/Request
The inverse would also be useful but not so simple, e.g., what size triangle do I need for a given incircle area.
[2]  2018/03/12 11:01   Male / 60 years old level or over / An engineer / - /
Purpose of use
As the previous comment stated, this was used to find the circular radius of the USPS Medium Tube (which ironically is a triangular prism) for the purposes of shipping items of circular cross-section (cylinders). The answer was about 1.5 inches, so the "tubes" are way too small for the items I wanted to ship inside. But that''s perfect for blueprints, its designed application.
[3]  2017/06/11 18:21   Female / 30 years old level / A homemaker / Very /
Purpose of use
To see how big a triangular cabinet needs to be to store my dinner plates.
Comment/Request
Thanks!
[4]  2016/12/09 15:01   Male / 20 years old level / A homemaker / Very /
Purpose of use
Shipping large photo prints in triangular "tubes" and wanted to know the equivalent diameter when compared with actual circular tubes

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