11 12 21 triangle
Obtuse scalene triangle.
Sides: a = 11 b = 12 c = 21Area: T = 49.1933495505
Perimeter: p = 44
Semiperimeter: s = 22
Angle ∠ A = α = 22.98109198075° = 22°58'51″ = 0.40110927158 rad
Angle ∠ B = β = 25.20987652968° = 25°12'32″ = 0.44399759548 rad
Angle ∠ C = γ = 131.8110314896° = 131°48'37″ = 2.3010523983 rad
Height: ha = 8.944427191
Height: hb = 8.19989159175
Height: hc = 4.685509481
Median: ma = 16.19441347407
Median: mb = 15.65224758425
Median: mc = 4.7176990566
Inradius: r = 2.23660679775
Circumradius: R = 14.08772282582
Vertex coordinates: A[21; 0] B[0; 0] C[9.95223809524; 4.685509481]
Centroid: CG[10.31774603175; 1.562169827]
Coordinates of the circumscribed circle: U[10.5; -9.39114855055]
Coordinates of the inscribed circle: I[10; 2.23660679775]
Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 157.0199080193° = 157°1'9″ = 0.40110927158 rad
∠ B' = β' = 154.7911234703° = 154°47'28″ = 0.44399759548 rad
∠ C' = γ' = 48.19896851042° = 48°11'23″ = 2.3010523983 rad
Calculate another triangle
How did we calculate this triangle?
Now we know the lengths of all three sides of the triangle and the triangle is uniquely determined. Next we calculate another its characteristics - same procedure as calculation of the triangle from the known three sides SSS.
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

6. Inradius

7. Circumradius
