# 11 18 25 triangle

### Obtuse scalene triangle.

Sides: a = 11   b = 18   c = 25

Area: T = 88.18216307402
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 23.07439180656° = 23°4'26″ = 0.40327158416 rad
Angle ∠ B = β = 39.8990390145° = 39°53'25″ = 0.69662186479 rad
Angle ∠ C = γ = 117.0365691789° = 117°2'8″ = 2.04326581641 rad

Height: ha = 16.03330237709
Height: hb = 9.79879589711
Height: hc = 7.05545304592

Median: ma = 21.07772389084
Median: mb = 17.08880074906
Median: mc = 8.1399410298

Inradius: r = 3.26659863237
Circumradius: R = 14.03435349847

Vertex coordinates: A[25; 0] B[0; 0] C[8.44; 7.05545304592]
Centroid: CG[11.14766666667; 2.35215101531]
Coordinates of the circumscribed circle: U[12.5; -6.37988795385]
Coordinates of the inscribed circle: I[9; 3.26659863237]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.9266081934° = 156°55'34″ = 0.40327158416 rad
∠ B' = β' = 140.1109609855° = 140°6'35″ = 0.69662186479 rad
∠ C' = γ' = 62.96443082106° = 62°57'52″ = 2.04326581641 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.