# 16 19 21 triangle

### Acute scalene triangle.

Sides: a = 16   b = 19   c = 21

Area: T = 145.4922267836
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 46.82664488927° = 46°49'35″ = 0.81772757102 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 73.17435511073° = 73°10'25″ = 1.27771193922 rad

Height: ha = 18.18765334795
Height: hb = 15.31549755617
Height: hc = 13.85664064606

Median: ma = 18.35875597507
Median: mb = 16.077015868
Median: mc = 14.08801278403

Inradius: r = 5.19661524227
Circumradius: R = 10.97696551146

Vertex coordinates: A[21; 0] B[0; 0] C[8; 13.85664064606]
Centroid: CG[9.66766666667; 4.61988021535]
Coordinates of the circumscribed circle: U[10.5; 3.17554264805]
Coordinates of the inscribed circle: I[9; 5.19661524227]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 133.1743551107° = 133°10'25″ = 0.81772757102 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 106.8266448893° = 106°49'35″ = 1.27771193922 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.