# 14 21 28 triangle

### Obtuse scalene triangle.

Sides: a = 14   b = 21   c = 28

Area: T = 142.3322137973
Perimeter: p = 63
Semiperimeter: s = 31.5

Angle ∠ A = α = 28.95550243719° = 28°57'18″ = 0.50553605103 rad
Angle ∠ B = β = 46.56774634422° = 46°34'3″ = 0.81327555614 rad
Angle ∠ C = γ = 104.4787512186° = 104°28'39″ = 1.82334765819 rad

Height: ha = 20.33331625676
Height: hb = 13.55554417117
Height: hc = 10.16765812838

Median: ma = 23.73881549409
Median: mb = 19.48771752699
Median: mc = 11.06879718106

Inradius: r = 4.51884805706
Circumradius: R = 14.45991378258

Vertex coordinates: A[28; 0] B[0; 0] C[9.625; 10.16765812838]
Centroid: CG[12.54216666667; 3.38988604279]
Coordinates of the circumscribed circle: U[14; -3.61547844565]
Coordinates of the inscribed circle: I[10.5; 4.51884805706]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 151.0454975628° = 151°2'42″ = 0.50553605103 rad
∠ B' = β' = 133.4332536558° = 133°25'57″ = 0.81327555614 rad
∠ C' = γ' = 75.52224878141° = 75°31'21″ = 1.82334765819 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.