# 4 28 29 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 28   c = 29

Area: T = 55.05439508119
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 7.79333663715° = 7°47'36″ = 0.1366019903 rad
Angle ∠ B = β = 71.66600018715° = 71°39'36″ = 1.25107029746 rad
Angle ∠ C = γ = 100.5476631757° = 100°32'48″ = 1.75548697759 rad

Height: ha = 27.5276975406
Height: hb = 3.9322425058
Height: hc = 3.79768241939

Median: ma = 28.43441344162
Median: mb = 15.2487950682
Median: mc = 13.7754977314

Inradius: r = 1.80550475676
Circumradius: R = 14.74991685524

Vertex coordinates: A[29; 0] B[0; 0] C[1.25986206897; 3.79768241939]
Centroid: CG[10.08662068966; 1.26656080646]
Coordinates of the circumscribed circle: U[14.5; -2.76996246011]
Coordinates of the inscribed circle: I[2.5; 1.80550475676]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 172.2076633629° = 172°12'24″ = 0.1366019903 rad
∠ B' = β' = 108.3439998128° = 108°20'24″ = 1.25107029746 rad
∠ C' = γ' = 79.4533368243° = 79°27'12″ = 1.75548697759 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    