# 5 13 15 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 13   c = 15

Area: T = 31.56224381188
Perimeter: p = 33
Semiperimeter: s = 16.5

Angle ∠ A = α = 18.88878819509° = 18°53'16″ = 0.33296557288 rad
Angle ∠ B = β = 57.31663611537° = 57°18'59″ = 11.0003592174 rad
Angle ∠ C = γ = 103.7965756895° = 103°47'45″ = 1.81215777074 rad

Height: ha = 12.62549752475
Height: hb = 4.85657597106
Height: hc = 4.20883250825

Median: ma = 13.81112273169
Median: mb = 9.09767026993
Median: mc = 6.38435726674

Inradius: r = 1.91328750375
Circumradius: R = 7.72327874185

Vertex coordinates: A[15; 0] B[0; 0] C[2.7; 4.20883250825]
Centroid: CG[5.9; 1.40327750275]
Coordinates of the circumscribed circle: U[7.5; -1.8421587769]
Coordinates of the inscribed circle: I[3.5; 1.91328750375]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.1122118049° = 161°6'44″ = 0.33296557288 rad
∠ B' = β' = 122.6843638846° = 122°41'1″ = 11.0003592174 rad
∠ C' = γ' = 76.20442431047° = 76°12'15″ = 1.81215777074 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.