# 19 20 28 triangle

### Obtuse scalene triangle.

Sides: a = 19   b = 20   c = 28

Area: T = 189.9132973491
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 42.70878707931° = 42°42'28″ = 0.74553929619 rad
Angle ∠ B = β = 45.55879131999° = 45°33'28″ = 0.79551355857 rad
Angle ∠ C = γ = 91.7344216007° = 91°44'3″ = 1.60110641061 rad

Height: ha = 19.99108393148
Height: hb = 18.9911297349
Height: hc = 13.56552123922

Median: ma = 22.43997767846
Median: mb = 21.73770651193
Median: mc = 13.58330777072

Inradius: r = 5.66990439848
Circumradius: R = 14.00664154181

Vertex coordinates: A[28; 0] B[0; 0] C[13.30435714286; 13.56552123922]
Centroid: CG[13.76878571429; 4.52217374641]
Coordinates of the circumscribed circle: U[14; -0.42438783613]
Coordinates of the inscribed circle: I[13.5; 5.66990439848]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.2922129207° = 137°17'32″ = 0.74553929619 rad
∠ B' = β' = 134.44220868° = 134°26'32″ = 0.79551355857 rad
∠ C' = γ' = 88.2665783993° = 88°15'57″ = 1.60110641061 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.