# 14 17 21 triangle

### Acute scalene triangle.

Sides: a = 14   b = 17   c = 21

Area: T = 118.4910505949
Perimeter: p = 52
Semiperimeter: s = 26

Angle ∠ A = α = 41.59112771434° = 41°35'29″ = 0.72659047263 rad
Angle ∠ B = β = 53.71325429149° = 53°42'45″ = 0.93774607235 rad
Angle ∠ C = γ = 84.69661799417° = 84°41'46″ = 1.47882272038 rad

Height: ha = 16.92772151355
Height: hb = 13.94400595234
Height: hc = 11.28548100904

Median: ma = 17.77663888346
Median: mb = 15.69223548265
Median: mc = 11.5

Inradius: r = 4.55773271519
Circumradius: R = 10.54551486598

Vertex coordinates: A[21; 0] B[0; 0] C[8.28657142857; 11.28548100904]
Centroid: CG[9.76219047619; 3.76216033635]
Coordinates of the circumscribed circle: U[10.5; 0.97547616408]
Coordinates of the inscribed circle: I[9; 4.55773271519]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.4098722857° = 138°24'31″ = 0.72659047263 rad
∠ B' = β' = 126.2877457085° = 126°17'15″ = 0.93774607235 rad
∠ C' = γ' = 95.30438200583° = 95°18'14″ = 1.47882272038 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.