# 18 27 30 triangle

### Acute scalene triangle.

Sides: a = 18   b = 27   c = 30

Area: T = 239.9710701337
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 36.33660575146° = 36°20'10″ = 0.63441838408 rad
Angle ∠ B = β = 62.7220387264° = 62°43'13″ = 1.09546772659 rad
Angle ∠ C = γ = 80.94435552214° = 80°56'37″ = 1.41327315469 rad

Height: ha = 26.66334112596
Height: hb = 17.77656075064
Height: hc = 15.99880467558

Median: ma = 27.08332051279
Median: mb = 20.73304124416
Median: mc = 17.36437553542

Inradius: r = 6.39992187023
Circumradius: R = 15.18993542824

Vertex coordinates: A[30; 0] B[0; 0] C[8.25; 15.99880467558]
Centroid: CG[12.75; 5.33326822519]
Coordinates of the circumscribed circle: U[15; 2.39109168778]
Coordinates of the inscribed circle: I[10.5; 6.39992187023]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.6643942485° = 143°39'50″ = 0.63441838408 rad
∠ B' = β' = 117.2879612736° = 117°16'47″ = 1.09546772659 rad
∠ C' = γ' = 99.05664447786° = 99°3'23″ = 1.41327315469 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.