`r = ( "a" * "b" * "c" ) / (4sqrt(( "a" + "b" + "c" )/2(( "a" + "b" + "c" )/2- "a" )(( "a" + "b" + "c" )/2- "b" )(( "a" + "b" + "c" )/2- "c" )))`

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The Radius of a Circle Around a Triangle formula computes the Circle Around a Triangleradius of a circle (r) that perfectly circumscribes the outside of a triangle.  

INSTRUCTIONS: Choose your preferred length units and enter the following:

• (a)  The length of side a of the triangle
• (b)  The length of side b of the triangle
• (c)  The length of side c of the triangle

Radius: The calculator will compute the radius (r) of the circle that would go around the triangle in meters.  However, this can be automatically converted to other length units via the pull-down menu.

Related Circle Calculators:

• Circle Area -  This computes the area of a circle given the radius (A = π r²).
• Segment Area f(r,θ) - This computes the area of an arc segment of a circle given the radius (r) and angle (θ)
• Segment Area f(r,h) - This computes the area of an arc segment of a circle given radius (r) and the depth (h) into the circle.
• Sector Area f(r,Θ)- This computes the area of a sector (pie slice) of a circle given the radius (r) and angle (Θ).
• Area of Annulus- This computes the area of an annulus (ring) given the inner radius (r) and outer radius (R).
• Radius -Center to a Point - This computes the radius of a circle given the center point (h,k) and any other point (x,y) on the circle.
• Circumference -  This computes the circumference of a circle given the radius (C = 2 π r).
• Arc Lengths - This computes the length of a cord segment (arc length) on a circle given the radius (r) and angle (Θ)
• Circle within a Triangle -  This computes the radius of a circle inscribed within a triangle given the length of the three sides (a,b,c) of the triangle.
• Circle around a Triangle - This computes the radius of a circle that circumscribes a triangle given the length of the three sides (a,b,c) of the triangle.
• Radius from Circumference - This computes the radius of a circle given the circumference.
• Circumference from Area - This computes the circumference of a circle given the area.
• Radius from Area - This computes the radius of a circle given the area.
• Radius from Cord-  This computes the radius of a circle based on the length of a cord and the cord's center height.