# 16 18 26 triangle

### Obtuse scalene triangle.

Sides: a = 16   b = 18   c = 26

Area: T = 141.9865914794
Perimeter: p = 60
Semiperimeter: s = 30

Angle ∠ A = α = 37.35768519729° = 37°21'25″ = 0.65220000651 rad
Angle ∠ B = β = 43.04990798002° = 43°2'57″ = 0.75113481825 rad
Angle ∠ C = γ = 99.59440682269° = 99°35'39″ = 1.7388244406 rad

Height: ha = 17.74882393493
Height: hb = 15.77662127549
Height: hc = 10.92219934457

Median: ma = 20.88106130178
Median: mb = 19.62114168703
Median: mc = 11

Inradius: r = 4.73328638265
Circumradius: R = 13.18444063738

Vertex coordinates: A[26; 0] B[0; 0] C[11.69223076923; 10.92219934457]
Centroid: CG[12.56441025641; 3.64106644819]
Coordinates of the circumscribed circle: U[13; -2.19774010623]
Coordinates of the inscribed circle: I[12; 4.73328638265]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.6433148027° = 142°38'35″ = 0.65220000651 rad
∠ B' = β' = 136.95109202° = 136°57'3″ = 0.75113481825 rad
∠ C' = γ' = 80.40659317731° = 80°24'21″ = 1.7388244406 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    