# 13 14 21 triangle

### Obtuse scalene triangle.

Sides: a = 13   b = 14   c = 21

Area: T = 88.99443818451
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 37.25879160013° = 37°15'29″ = 0.65502733067 rad
Angle ∠ B = β = 40.69105605975° = 40°41'26″ = 0.71101842569 rad
Angle ∠ C = γ = 102.0521523401° = 102°3'5″ = 1.781113509 rad

Height: ha = 13.69114433608
Height: hb = 12.71334831207
Height: hc = 8.47656554138

Median: ma = 16.62107701386
Median: mb = 16
Median: mc = 8.5

Inradius: r = 3.70880992435
Circumradius: R = 10.73766328097

Vertex coordinates: A[21; 0] B[0; 0] C[9.85771428571; 8.47656554138]
Centroid: CG[10.28657142857; 2.82552184713]
Coordinates of the circumscribed circle: U[10.5; -2.24217145427]
Coordinates of the inscribed circle: I[10; 3.70880992435]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.7422083999° = 142°44'31″ = 0.65502733067 rad
∠ B' = β' = 139.3099439402° = 139°18'34″ = 0.71101842569 rad
∠ C' = γ' = 77.94884765988° = 77°56'55″ = 1.781113509 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.