5 18 20 triangle

Obtuse scalene triangle.

Sides: a = 5   b = 18   c = 20

Area: T = 43.15659671424
Perimeter: p = 43
Semiperimeter: s = 21.5

Angle ∠ A = α = 13.8722102735° = 13°52'20″ = 0.24221138669 rad
Angle ∠ B = β = 59.66986476367° = 59°40'7″ = 1.04114143615 rad
Angle ∠ C = γ = 106.4599249628° = 106°27'33″ = 1.85880644252 rad

Height: ha = 17.2622386857
Height: hb = 4.79551074603
Height: hc = 4.31655967142

Median: ma = 18.86113361139
Median: mb = 11.46773449412
Median: mc = 8.63113382508

Vertex coordinates: A[20; 0] B[0; 0] C[2.525; 4.31655967142]
Centroid: CG[7.50883333333; 1.43985322381]
Coordinates of the circumscribed circle: U[10; -2.95444002473]
Coordinates of the inscribed circle: I[3.5; 2.00772542857]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 166.1287897265° = 166°7'40″ = 0.24221138669 rad
∠ B' = β' = 120.3311352363° = 120°19'53″ = 1.04114143615 rad
∠ C' = γ' = 73.54107503717° = 73°32'27″ = 1.85880644252 rad

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    