# 9 19 25 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 19   c = 25

Area: T = 72.2330101066
Perimeter: p = 53
Semiperimeter: s = 26.5

Angle ∠ A = α = 17.70656342953° = 17°42'20″ = 0.30990216146 rad
Angle ∠ B = β = 39.94545051898° = 39°56'40″ = 0.69771631336 rad
Angle ∠ C = γ = 122.3549860515° = 122°20'59″ = 2.13554079053 rad

Height: ha = 16.05111335702
Height: hb = 7.60331685333
Height: hc = 5.77884080853

Median: ma = 21.74328149052
Median: mb = 16.21095650774
Median: mc = 8.04767384697

Inradius: r = 2.72656641912
Circumradius: R = 14.79664627521

Vertex coordinates: A[25; 0] B[0; 0] C[6.9; 5.77884080853]
Centroid: CG[10.63333333333; 1.92661360284]
Coordinates of the circumscribed circle: U[12.5; -7.91774055077]
Coordinates of the inscribed circle: I[7.5; 2.72656641912]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.2944365705° = 162°17'40″ = 0.30990216146 rad
∠ B' = β' = 140.055549481° = 140°3'20″ = 0.69771631336 rad
∠ C' = γ' = 57.65501394851° = 57°39'1″ = 2.13554079053 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    