# 18 20 29 triangle

### Obtuse scalene triangle.

Sides: a = 18   b = 20   c = 29

Area: T = 177.6087537847
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 37.76661251952° = 37°45'58″ = 0.65991432304 rad
Angle ∠ B = β = 42.88218397473° = 42°52'55″ = 0.74884292929 rad
Angle ∠ C = γ = 99.35220350576° = 99°21'7″ = 1.73440201303 rad

Height: ha = 19.73441708719
Height: hb = 17.76107537847
Height: hc = 12.24987957136

Median: ma = 23.22771392987
Median: mb = 21.96658826365
Median: mc = 12.31986849948

Inradius: r = 5.30217175477
Circumradius: R = 14.69553222349

Vertex coordinates: A[29; 0] B[0; 0] C[13.19896551724; 12.24987957136]
Centroid: CG[14.06332183908; 4.08329319045]
Coordinates of the circumscribed circle: U[14.5; -2.38879898632]
Coordinates of the inscribed circle: I[13.5; 5.30217175477]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.2343874805° = 142°14'2″ = 0.65991432304 rad
∠ B' = β' = 137.1188160253° = 137°7'5″ = 0.74884292929 rad
∠ C' = γ' = 80.64879649424° = 80°38'53″ = 1.73440201303 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.