Triangle calculator

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

Acute isosceles triangle.

Sides: a = 66   b = 66   c = 77

Area: T = 2063.884370251
Perimeter: p = 209
Semiperimeter: s = 104.5

Angle ∠ A = α = 54.31546652873° = 54°18'53″ = 0.94879697414 rad
Angle ∠ B = β = 54.31546652873° = 54°18'53″ = 0.94879697414 rad
Angle ∠ C = γ = 71.37106694253° = 71°22'14″ = 1.24656531708 rad

Height: ha = 62.54219303792
Height: hb = 62.54219303792
Height: hc = 53.60773688964

Median: ma = 63.66771029653
Median: mb = 63.66771029653
Median: mc = 53.60773688964

Inradius: r = 19.75500832776
Circumradius: R = 40.62987427426

Vertex coordinates: A[77; 0] B[0; 0] C[38.5; 53.60773688964]
Centroid: CG[38.5; 17.86991229655]
Coordinates of the circumscribed circle: U[38.5; 12.97986261539]
Coordinates of the inscribed circle: I[38.5; 19.75500832776]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 125.6855334713° = 125°41'7″ = 0.94879697414 rad
∠ B' = β' = 125.6855334713° = 125°41'7″ = 0.94879697414 rad
∠ C' = γ' = 108.6299330575° = 108°37'46″ = 1.24656531708 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     