# 11 21 26 triangle

### Obtuse scalene triangle.

Sides: a = 11   b = 21   c = 26

Area: T = 111.9298548637
Perimeter: p = 58
Semiperimeter: s = 29

Angle ∠ A = α = 24.20545008373° = 24°12'16″ = 0.42224482334 rad
Angle ∠ B = β = 51.51100302971° = 51°30'36″ = 0.89990196265 rad
Angle ∠ C = γ = 104.2855468866° = 104°17'8″ = 1.82201247937 rad

Height: ha = 20.35106452067
Height: hb = 10.6659861775
Height: hc = 8.61098883567

Median: ma = 22.98436898691
Median: mb = 16.97879268463
Median: mc = 10.58330052443

Inradius: r = 3.86596051254
Circumradius: R = 13.41548080922

Vertex coordinates: A[26; 0] B[0; 0] C[6.84661538462; 8.61098883567]
Centroid: CG[10.94987179487; 2.87699627856]
Coordinates of the circumscribed circle: U[13; -3.31101474513]
Coordinates of the inscribed circle: I[8; 3.86596051254]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 155.7955499163° = 155°47'44″ = 0.42224482334 rad
∠ B' = β' = 128.4989969703° = 128°29'24″ = 0.89990196265 rad
∠ C' = γ' = 75.71545311344° = 75°42'52″ = 1.82201247937 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.