# 12 18 27 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 18   c = 27

Area: T = 86.06106617451
Perimeter: p = 57
Semiperimeter: s = 28.5

Angle ∠ A = α = 20.74219164807° = 20°44'31″ = 0.36220147358 rad
Angle ∠ B = β = 32.08991838633° = 32°5'21″ = 0.56600619127 rad
Angle ∠ C = γ = 127.1698899656° = 127°10'8″ = 2.22195160051 rad

Height: ha = 14.34334436242
Height: hb = 9.56222957495
Height: hc = 6.3754863833

Median: ma = 22.14772345904
Median: mb = 18.8554707635
Median: mc = 7.1943747285

Inradius: r = 3.02196723419
Circumradius: R = 16.9421538334

Vertex coordinates: A[27; 0] B[0; 0] C[10.16766666667; 6.3754863833]
Centroid: CG[12.38988888889; 2.1254954611]
Coordinates of the circumscribed circle: U[13.5; -10.23655127434]
Coordinates of the inscribed circle: I[10.5; 3.02196723419]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 159.2588083519° = 159°15'29″ = 0.36220147358 rad
∠ B' = β' = 147.9110816137° = 147°54'39″ = 0.56600619127 rad
∠ C' = γ' = 52.8311100344° = 52°49'52″ = 2.22195160051 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.