# 9 19 20 triangle

### Acute scalene triangle.

Sides: a = 9   b = 19   c = 20

Area: T = 84.85328137424
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 26.52553520166° = 26°31'31″ = 0.46329547279 rad
Angle ∠ B = β = 70.52987793655° = 70°31'44″ = 1.23109594173 rad
Angle ∠ C = γ = 82.94658686179° = 82°56'45″ = 1.44876785083 rad

Height: ha = 18.85661808316
Height: hb = 8.93218751308
Height: hc = 8.48552813742

Median: ma = 18.98802528961
Median: mb = 12.25876506721
Median: mc = 11

Inradius: r = 3.53655339059
Circumradius: R = 10.07662716319

Vertex coordinates: A[20; 0] B[0; 0] C[3; 8.48552813742]
Centroid: CG[7.66766666667; 2.82884271247]
Coordinates of the circumscribed circle: U[10; 1.23774368671]
Coordinates of the inscribed circle: I[5; 3.53655339059]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 153.4754647983° = 153°28'29″ = 0.46329547279 rad
∠ B' = β' = 109.4711220634° = 109°28'16″ = 1.23109594173 rad
∠ C' = γ' = 97.05441313821° = 97°3'15″ = 1.44876785083 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.