# 10 20 28 triangle

### Obtuse scalene triangle.

Sides: a = 10   b = 20   c = 28

Area: T = 70.42201675658
Perimeter: p = 58
Semiperimeter: s = 29

Angle ∠ A = α = 14.56663276483° = 14°33'59″ = 0.25442303774 rad
Angle ∠ B = β = 30.1998757023° = 30°11'56″ = 0.52770677401 rad
Angle ∠ C = γ = 135.2354915329° = 135°14'6″ = 2.36602945361 rad

Height: ha = 14.08440335132
Height: hb = 7.04220167566
Height: hc = 5.0330011969

Median: ma = 23.81217617996
Median: mb = 18.49332420089
Median: mc = 7.34884692283

Inradius: r = 2.42882816402
Circumradius: R = 19.88106683993

Vertex coordinates: A[28; 0] B[0; 0] C[8.64328571429; 5.0330011969]
Centroid: CG[12.21442857143; 1.67766706563]
Coordinates of the circumscribed circle: U[14; -14.11552745635]
Coordinates of the inscribed circle: I[9; 2.42882816402]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 165.4343672352° = 165°26'1″ = 0.25442303774 rad
∠ B' = β' = 149.8011242977° = 149°48'4″ = 0.52770677401 rad
∠ C' = γ' = 44.76550846713° = 44°45'54″ = 2.36602945361 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.