Triangle calculator

Please enter what you know about the triangle:
You have entered side a, b and c (as equilateral triangle).

Equilateral triangle.

Sides: a = 55   b = 55   c = 55

Area: T = 1309.863342322
Perimeter: p = 165
Semiperimeter: s = 82.5

Angle ∠ A = α = 60° = 1.04771975512 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 60° = 1.04771975512 rad

Height: ha = 47.63113972081
Height: hb = 47.63113972081
Height: hc = 47.63113972081

Median: ma = 47.63113972081
Median: mb = 47.63113972081
Median: mc = 47.63113972081

Inradius: r = 15.87771324027
Circumradius: R = 31.75442648054

Vertex coordinates: A[55; 0] B[0; 0] C[27.5; 47.63113972081]
Centroid: CG[27.5; 15.87771324027]
Coordinates of the circumscribed circle: U[27.5; 15.87771324027]
Coordinates of the inscribed circle: I[27.5; 15.87771324027]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 120° = 1.04771975512 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 120° = 1.04771975512 rad

How did we calculate this triangle?

1. Input data entered: side a, b and c (as equilateral triangle). 2. The triangle circumference is the sum of the lengths of its three sides 3. Semiperimeter of the triangle 4. The triangle area using Heron's formula 5. Calculate the heights of the triangle from its area. 6. Calculation of the inner angles of the triangle using a Law of Cosines    