# 13 21 29 triangle

### Obtuse scalene triangle.

Sides: a = 13   b = 21   c = 29

Area: T = 123.6821799389
Perimeter: p = 63
Semiperimeter: s = 31.5

Angle ∠ A = α = 23.9655090985° = 23°57'54″ = 0.41882697432 rad
Angle ∠ B = β = 41.00659095274° = 41°21″ = 0.7165688134 rad
Angle ∠ C = γ = 115.0298999488° = 115°1'44″ = 2.00876347763 rad

Height: ha = 19.02879691367
Height: hb = 11.77992189894
Height: hc = 8.53297792682

Median: ma = 24.46993686065
Median: mb = 19.86883164863
Median: mc = 9.7343961167

Inradius: r = 3.92664063298
Circumradius: R = 16.00327587712

Vertex coordinates: A[29; 0] B[0; 0] C[9.81103448276; 8.53297792682]
Centroid: CG[12.93767816092; 2.84332597561]
Coordinates of the circumscribed circle: U[14.5; -6.77703979416]
Coordinates of the inscribed circle: I[10.5; 3.92664063298]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.0354909015° = 156°2'6″ = 0.41882697432 rad
∠ B' = β' = 138.9944090473° = 138°59'39″ = 0.7165688134 rad
∠ C' = γ' = 64.97110005124° = 64°58'16″ = 2.00876347763 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.