# 12 24 30 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 24   c = 30

Area: T = 136.7888157382
Perimeter: p = 66
Semiperimeter: s = 33

Angle ∠ A = α = 22.33216450092° = 22°19'54″ = 0.39897607328 rad
Angle ∠ B = β = 49.45883981265° = 49°27'30″ = 0.86332118901 rad
Angle ∠ C = γ = 108.2109956864° = 108°12'36″ = 1.88986200307 rad

Height: ha = 22.79880262304
Height: hb = 11.39990131152
Height: hc = 9.11992104921

Median: ma = 26.4955282599
Median: mb = 19.44222220952
Median: mc = 11.61989500386

Inradius: r = 4.14550956782
Circumradius: R = 15.7910840679

Vertex coordinates: A[30; 0] B[0; 0] C[7.8; 9.11992104921]
Centroid: CG[12.6; 3.04397368307]
Coordinates of the circumscribed circle: U[15; -4.93546377122]
Coordinates of the inscribed circle: I[9; 4.14550956782]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 157.6688354991° = 157°40'6″ = 0.39897607328 rad
∠ B' = β' = 130.5421601874° = 130°32'30″ = 0.86332118901 rad
∠ C' = γ' = 71.79900431357° = 71°47'24″ = 1.88986200307 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.