Triangle calculator

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

Obtuse isosceles triangle.

Sides: a = 80   b = 80   c = 120

Area: T = 3174.902157328
Perimeter: p = 280
Semiperimeter: s = 140

Angle ∠ A = α = 41.41096221093° = 41°24'35″ = 0.72327342478 rad
Angle ∠ B = β = 41.41096221093° = 41°24'35″ = 0.72327342478 rad
Angle ∠ C = γ = 97.18107557815° = 97°10'51″ = 1.6966124158 rad

Height: ha = 79.37325393319
Height: hb = 79.37325393319
Height: hc = 52.91550262213

Median: ma = 93.80883151965
Median: mb = 93.80883151965
Median: mc = 52.91550262213

Inradius: r = 22.67878683806
Circumradius: R = 60.47443156815

Vertex coordinates: A[120; 0] B[0; 0] C[60; 52.91550262213]
Centroid: CG[60; 17.63883420738]
Coordinates of the circumscribed circle: U[60; -7.55992894602]
Coordinates of the inscribed circle: I[60; 22.67878683806]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.5990377891° = 138°35'25″ = 0.72327342478 rad
∠ B' = β' = 138.5990377891° = 138°35'25″ = 0.72327342478 rad
∠ C' = γ' = 82.81992442185° = 82°49'9″ = 1.6966124158 rad

How did we calculate this triangle?

1. Input data entered: side a, b and c. 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     