# 18 20 27 triangle

### Obtuse scalene triangle.

Sides: a = 18   b = 20   c = 27

Area: T = 179.996565967
Perimeter: p = 65
Semiperimeter: s = 32.5

Angle ∠ A = α = 41.80990791939° = 41°48'33″ = 0.73297060892 rad
Angle ∠ B = β = 47.79330302502° = 47°47'35″ = 0.83441457374 rad
Angle ∠ C = γ = 90.39878905558° = 90°23'52″ = 1.57877408271 rad

Height: ha = 209.9995177411
Height: hb = 187.999565967
Height: hc = 13.33330118274

Median: ma = 21.98986334273
Median: mb = 20.65218764281
Median: mc = 13.40770876778

Inradius: r = 5.53883279898
Circumradius: R = 13.55003255326

Vertex coordinates: A[27; 0] B[0; 0] C[12.09325925926; 13.33330118274]
Centroid: CG[13.03108641975; 4.44443372758]
Coordinates of the circumscribed circle: U[13.5; -0.09437522606]
Coordinates of the inscribed circle: I[12.5; 5.53883279898]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.1910920806° = 138°11'27″ = 0.73297060892 rad
∠ B' = β' = 132.207696975° = 132°12'25″ = 0.83441457374 rad
∠ C' = γ' = 89.60221094442° = 89°36'8″ = 1.57877408271 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.