# 5 12 15 triangle

### Obtuse scalene triangle.

Sides: a = 5   b = 12   c = 15

Area: T = 26.53329983228
Perimeter: p = 32
Semiperimeter: s = 16

Angle ∠ A = α = 17.14662099989° = 17°8'46″ = 0.29992578187 rad
Angle ∠ B = β = 45.03656507165° = 45°2'8″ = 0.78660203858 rad
Angle ∠ C = γ = 117.8188139285° = 117°49'5″ = 2.05663144491 rad

Height: ha = 10.61331993291
Height: hb = 4.42221663871
Height: hc = 3.53877331097

Median: ma = 13.35110299228
Median: mb = 9.43439811321
Median: mc = 5.31550729064

Inradius: r = 1.65883123952
Circumradius: R = 8.48800065662

Vertex coordinates: A[15; 0] B[0; 0] C[3.53333333333; 3.53877331097]
Centroid: CG[6.17877777778; 1.17992443699]
Coordinates of the circumscribed circle: U[7.5; -3.95773363976]
Coordinates of the inscribed circle: I[4; 1.65883123952]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.8543790001° = 162°51'14″ = 0.29992578187 rad
∠ B' = β' = 134.9644349284° = 134°57'52″ = 0.78660203858 rad
∠ C' = γ' = 62.18218607153° = 62°10'55″ = 2.05663144491 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.