# 14 20 21 triangle

### Acute scalene triangle.

Sides: a = 14   b = 20   c = 21

Area: T = 134.533043336
Perimeter: p = 55
Semiperimeter: s = 27.5

Angle ∠ A = α = 39.83881498056° = 39°50'17″ = 0.6955306882 rad
Angle ∠ B = β = 66.23303095773° = 66°13'49″ = 1.15659369667 rad
Angle ∠ C = γ = 73.9321540617° = 73°55'54″ = 1.29903488048 rad

Height: ha = 19.21986333371
Height: hb = 13.4533043336
Height: hc = 12.81224222248

Median: ma = 19.27443352674
Median: mb = 14.78217454991
Median: mc = 13.7022189606

Inradius: r = 4.89220157585
Circumradius: R = 10.92768955974

Vertex coordinates: A[21; 0] B[0; 0] C[5.64328571429; 12.81224222248]
Centroid: CG[8.8810952381; 4.27108074083]
Coordinates of the circumscribed circle: U[10.5; 3.02444086029]
Coordinates of the inscribed circle: I[7.5; 4.89220157585]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.1621850194° = 140°9'43″ = 0.6955306882 rad
∠ B' = β' = 113.7769690423° = 113°46'11″ = 1.15659369667 rad
∠ C' = γ' = 106.0688459383° = 106°4'6″ = 1.29903488048 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.