Change Equation
Select an equation to solve for a different unknown



Scalene Triangle:
No sides have equal length
No angles are equal

Scalene Triangle Equations
These equations apply to any type of triangle. Reduced
equations for equilateral, right and isosceles are below.

	Perimeter
	Semiperimeter
	Area
	Area
	Base
	Height
	Angle Bisector of side a
	Angle Bisector of side b
	Angle Bisector of side c
	Median of side a
	Median of side b
	Median of side c
	Altitude of side a
	Altitude of side b
	Altitude of side c
	Circumscribed Circle Radius
	Inscribed Circle Radius

Law of Cosines

	length of side a
	angle of A

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Equilateral Triangle:
All three sides have equal length
All three angles are equal to 60 degrees

Equilateral Triangle Equations

	Perimeter
	Semiperimeter
	Area
	Altitude
	Median
	Angle Bisector
	Circumscribed Circle Radius
	Inscribed Circle Radius

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Right Triangle:
One angle is equal to 90 degrees

Right Triangle Equations

	Pythagorean Theorem
	Perimeter
	Semiperimeter
	Area
	Altitude of a
	Altitude of b
	Altitude of c
	Angle Bisector of a
	Angle Bisector of b
	Angle Bisector of c
	Median of a
	Median of b
	Median of c
	Inscribed Circle Radius
	Circumscribed Circle Radius

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Isosceles Triangle:
Two sides have equal length
Two angles are equal

Isosceles Triangle Equations

	Perimeter
	Semiperimeter
	Area
	Altitudes of sides a and c
	Altitude of side b
	Median of sides a and c
	Median of side b
	Angle Bisector of sides a and c
	Angle Bisector of side b
	Circumscribed Circle Radius
	Inscribed Circle Radius

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P	=	Perimeter
s	=	Semiperimeter
a	=	Length of side a
b	=	Length of side b
c	=	Length of side c
h	=	Altitude
m	=	Median
A	=	Angle A
B	=	Angle B
C	=	Angle C
t	=	Angle bisector
R	=	Circumscribed Circle Radius
r	=	Inscribed Circle Radius

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