# 19 21 28 triangle

### Acute scalene triangle.

Sides: a = 19   b = 21   c = 28

Area: T = 199.4499241663
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 42.71986445144° = 42°43'7″ = 0.74655809988 rad
Angle ∠ B = β = 48.57438511071° = 48°34'26″ = 0.84877736322 rad
Angle ∠ C = γ = 88.70875043785° = 88°42'27″ = 1.54882380226 rad

Height: ha = 20.99546570172
Height: hb = 18.99551658727
Height: hc = 14.24663744045

Median: ma = 22.85327897641
Median: mb = 21.5
Median: mc = 14.31878210633

Inradius: r = 5.86661541666
Circumradius: R = 14.00435628951

Vertex coordinates: A[28; 0] B[0; 0] C[12.57114285714; 14.24663744045]
Centroid: CG[13.52438095238; 4.74987914682]
Coordinates of the circumscribed circle: U[14; 0.31658698397]
Coordinates of the inscribed circle: I[13; 5.86661541666]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.2811355486° = 137°16'53″ = 0.74655809988 rad
∠ B' = β' = 131.4266148893° = 131°25'34″ = 0.84877736322 rad
∠ C' = γ' = 91.29224956215° = 91°17'33″ = 1.54882380226 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.