# 12 20 27 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 20   c = 27

Area: T = 110.729911767
Perimeter: p = 59
Semiperimeter: s = 29.5

Angle ∠ A = α = 24.21216095233° = 24°12'42″ = 0.42325723034 rad
Angle ∠ B = β = 43.11987806049° = 43°7'8″ = 0.7532564691 rad
Angle ∠ C = γ = 112.6769609872° = 112°40'11″ = 1.96664556592 rad

Height: ha = 18.4554852945
Height: hb = 11.0732911767
Height: hc = 8.20221568645

Median: ma = 22.98991278651
Median: mb = 18.34439363278
Median: mc = 9.47436476607

Inradius: r = 3.75435294125
Circumradius: R = 14.63302981012

Vertex coordinates: A[27; 0] B[0; 0] C[8.75992592593; 8.20221568645]
Centroid: CG[11.92197530864; 2.73440522882]
Coordinates of the circumscribed circle: U[13.5; -5.63987607265]
Coordinates of the inscribed circle: I[9.5; 3.75435294125]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 155.7888390477° = 155°47'18″ = 0.42325723034 rad
∠ B' = β' = 136.8811219395° = 136°52'52″ = 0.7532564691 rad
∠ C' = γ' = 67.33303901282° = 67°19'49″ = 1.96664556592 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.