# 19 19 20 triangle

### Acute isosceles triangle.

Sides: a = 19   b = 19   c = 20

Area: T = 161.5554944214
Perimeter: p = 58
Semiperimeter: s = 29

Angle ∠ A = α = 58.24331361407° = 58°14'35″ = 1.01765344923 rad
Angle ∠ B = β = 58.24331361407° = 58°14'35″ = 1.01765344923 rad
Angle ∠ C = γ = 63.51437277186° = 63°30'49″ = 1.10985236689 rad

Height: ha = 17.00657836015
Height: hb = 17.00657836015
Height: hc = 16.15554944214

Median: ma = 17.03767250374
Median: mb = 17.03767250374
Median: mc = 16.15554944214

Inradius: r = 5.57108601453
Circumradius: R = 11.17326695137

Vertex coordinates: A[20; 0] B[0; 0] C[10; 16.15554944214]
Centroid: CG[10; 5.38551648071]
Coordinates of the circumscribed circle: U[10; 4.98328249078]
Coordinates of the inscribed circle: I[10; 5.57108601453]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 121.7576863859° = 121°45'25″ = 1.01765344923 rad
∠ B' = β' = 121.7576863859° = 121°45'25″ = 1.01765344923 rad
∠ C' = γ' = 116.4866272281° = 116°29'11″ = 1.10985236689 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.