# 12 20 29 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 20   c = 29

Area: T = 94.27105547878
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 18.97698692° = 18°58'12″ = 0.33110866762 rad
Angle ∠ B = β = 32.80552205984° = 32°48'19″ = 0.57325591113 rad
Angle ∠ C = γ = 128.2254910202° = 128°13'30″ = 2.23879468661 rad

Height: ha = 15.71217591313
Height: hb = 9.42770554788
Height: hc = 6.50114175716

Median: ma = 24.17664348075
Median: mb = 19.81216127562
Median: mc = 7.85881168228

Inradius: r = 3.09108378619
Circumradius: R = 18.45875131006

Vertex coordinates: A[29; 0] B[0; 0] C[10.08662068966; 6.50114175716]
Centroid: CG[13.02987356322; 2.16771391905]
Coordinates of the circumscribed circle: U[14.5; -11.4210586231]
Coordinates of the inscribed circle: I[10.5; 3.09108378619]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.03301308° = 161°1'48″ = 0.33110866762 rad
∠ B' = β' = 147.1954779402° = 147°11'41″ = 0.57325591113 rad
∠ C' = γ' = 51.77550897984° = 51°46'30″ = 2.23879468661 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.