# 16 21 28 triangle

### Obtuse scalene triangle.

Sides: a = 16   b = 21   c = 28

Area: T = 166.5866126373
Perimeter: p = 65
Semiperimeter: s = 32.5

Angle ∠ A = α = 34.51548264544° = 34°30'53″ = 0.60223973624 rad
Angle ∠ B = β = 48.0476537002° = 48°2'48″ = 0.83985702649 rad
Angle ∠ C = γ = 97.43986365436° = 97°26'19″ = 1.70106250263 rad

Height: ha = 20.82332657966
Height: hb = 15.86553453689
Height: hc = 11.89990090267

Median: ma = 23.42200768573
Median: mb = 20.242228248
Median: mc = 12.34990890352

Inradius: r = 5.12657269653
Circumradius: R = 14.11988228048

Vertex coordinates: A[28; 0] B[0; 0] C[10.69664285714; 11.89990090267]
Centroid: CG[12.89988095238; 3.96663363422]
Coordinates of the circumscribed circle: U[14; -1.82878833095]
Coordinates of the inscribed circle: I[11.5; 5.12657269653]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.4855173546° = 145°29'7″ = 0.60223973624 rad
∠ B' = β' = 131.9533462998° = 131°57'12″ = 0.83985702649 rad
∠ C' = γ' = 82.56113634564° = 82°33'41″ = 1.70106250263 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.