# 6 16 21 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 16   c = 21

Area: T = 30.27327187415
Perimeter: p = 43
Semiperimeter: s = 21.5

Angle ∠ A = α = 10.38111039012° = 10°22'52″ = 0.18111844431 rad
Angle ∠ B = β = 28.71993267538° = 28°43'10″ = 0.50112468108 rad
Angle ∠ C = γ = 140.9899569345° = 140°53'58″ = 2.45991613997 rad

Height: ha = 10.09109062472
Height: hb = 3.78440898427
Height: hc = 2.88331160706

Median: ma = 18.42655257727
Median: mb = 13.21098448136
Median: mc = 5.97991303716

Inradius: r = 1.40880334298
Circumradius: R = 16.64986533405

Vertex coordinates: A[21; 0] B[0; 0] C[5.26219047619; 2.88331160706]
Centroid: CG[8.7543968254; 0.96110386902]
Coordinates of the circumscribed circle: U[10.5; -12.92200486861]
Coordinates of the inscribed circle: I[5.5; 1.40880334298]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 169.6198896099° = 169°37'8″ = 0.18111844431 rad
∠ B' = β' = 151.2810673246° = 151°16'50″ = 0.50112468108 rad
∠ C' = γ' = 39.11004306549° = 39°6'2″ = 2.45991613997 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.