Triangle calculator SSS - result

Please enter the triangle sides:

Obtuse isosceles triangle.

Sides: a = 21   b = 21   c = 30

Area: T = 220.4544076851
Perimeter: p = 72
Semiperimeter: s = 36

Angle ∠ A = α = 44.41553085972° = 44°24'55″ = 0.77551933733 rad
Angle ∠ B = β = 44.41553085972° = 44°24'55″ = 0.77551933733 rad
Angle ∠ C = γ = 91.16993828056° = 91°10'10″ = 1.5911205907 rad

Height: ha = 20.99656263667
Height: hb = 20.99656263667
Height: hc = 14.69769384567

Median: ma = 23.67696007571
Median: mb = 23.67696007571
Median: mc = 14.69769384567

Inradius: r = 6.1243724357
Circumradius: R = 15.00331246745

Vertex coordinates: A[30; 0] B[0; 0] C[15; 14.69769384567]
Centroid: CG[15; 4.89989794856]
Coordinates of the circumscribed circle: U[15; -0.30661862178]
Coordinates of the inscribed circle: I[15; 6.1243724357]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 135.5854691403° = 135°35'5″ = 0.77551933733 rad
∠ B' = β' = 135.5854691403° = 135°35'5″ = 0.77551933733 rad
∠ C' = γ' = 88.83106171944° = 88°49'50″ = 1.5911205907 rad

How did we calculate this triangle?

1. The triangle circumference is the sum of the lengths of its three sides 2. Semiperimeter of the triangle 3. The triangle area using Heron's formula 4. Calculate the heights of the triangle from its area. 5. Calculation of the inner angles of the triangle using a Law of Cosines     