# 3 26 28 triangle

### Obtuse scalene triangle.

Sides: a = 3   b = 26   c = 28

Area: T = 30.14402969461
Perimeter: p = 57
Semiperimeter: s = 28.5

Angle ∠ A = α = 4.75497013846° = 4°44'59″ = 0.08328979276 rad
Angle ∠ B = β = 45.85988345181° = 45°51'32″ = 0.88003876535 rad
Angle ∠ C = γ = 129.3911464097° = 129°23'29″ = 2.25883070725 rad

Height: ha = 20.09435312974
Height: hb = 2.31884843805
Height: hc = 2.15328783533

Median: ma = 26.97768419204
Median: mb = 15.0833103129
Median: mc = 12.10437184369

Inradius: r = 1.05875542788
Circumradius: R = 18.11552827053

Vertex coordinates: A[28; 0] B[0; 0] C[2.08992857143; 2.15328783533]
Centroid: CG[10.03297619048; 0.71876261178]
Coordinates of the circumscribed circle: U[14; -11.49662371014]
Coordinates of the inscribed circle: I[2.5; 1.05875542788]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 175.2550298615° = 175°15'1″ = 0.08328979276 rad
∠ B' = β' = 134.1411165482° = 134°8'28″ = 0.88003876535 rad
∠ C' = γ' = 50.60985359027° = 50°36'31″ = 2.25883070725 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    