# 20 22 28 triangle

### Acute scalene triangle.

Sides: a = 20   b = 22   c = 28

Area: T = 218.5754929944
Perimeter: p = 70
Semiperimeter: s = 35

Angle ∠ A = α = 45.20771662976° = 45°12'26″ = 0.78990138974 rad
Angle ∠ B = β = 51.31878125465° = 51°19'4″ = 0.89656647939 rad
Angle ∠ C = γ = 83.47550211559° = 83°28'30″ = 1.45769139623 rad

Height: ha = 21.85774929944
Height: hb = 19.87704481767
Height: hc = 15.6122494996

Median: ma = 23.10884400166
Median: mb = 21.70325344142
Median: mc = 15.68443871414

Inradius: r = 6.24549979984
Circumradius: R = 14.09112775348

Vertex coordinates: A[28; 0] B[0; 0] C[12.5; 15.6122494996]
Centroid: CG[13.5; 5.20441649987]
Coordinates of the circumscribed circle: U[14; 1.60112815381]
Coordinates of the inscribed circle: I[13; 6.24549979984]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.7932833702° = 134°47'34″ = 0.78990138974 rad
∠ B' = β' = 128.6822187453° = 128°40'56″ = 0.89656647939 rad
∠ C' = γ' = 96.52549788441° = 96°31'30″ = 1.45769139623 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.