# 8 21 26 triangle

### Obtuse scalene triangle.

Sides: a = 8   b = 21   c = 26

Area: T = 72.30879352492
Perimeter: p = 55
Semiperimeter: s = 27.5

Angle ∠ A = α = 15.35988855808° = 15°21'32″ = 0.26880631228 rad
Angle ∠ B = β = 44.04986256741° = 44°2'55″ = 0.7698793549 rad
Angle ∠ C = γ = 120.5922488745° = 120°35'33″ = 2.10547359818 rad

Height: ha = 18.07769838123
Height: hb = 6.88664700237
Height: hc = 5.56221488653

Median: ma = 23.29216293977
Median: mb = 16.11767614613
Median: mc = 9.13878334412

Inradius: r = 2.62993794636
Circumradius: R = 15.10220769192

Vertex coordinates: A[26; 0] B[0; 0] C[5.75; 5.56221488653]
Centroid: CG[10.58333333333; 1.85440496218]
Coordinates of the circumscribed circle: U[13; -7.68658784321]
Coordinates of the inscribed circle: I[6.5; 2.62993794636]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 164.6411114419° = 164°38'28″ = 0.26880631228 rad
∠ B' = β' = 135.9511374326° = 135°57'5″ = 0.7698793549 rad
∠ C' = γ' = 59.40875112549° = 59°24'27″ = 2.10547359818 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.