# 12 18 23 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 18   c = 23

Area: T = 106.9187900746
Perimeter: p = 53
Semiperimeter: s = 26.5

Angle ∠ A = α = 31.09985459112° = 31°5'55″ = 0.54327720187 rad
Angle ∠ B = β = 50.78439487166° = 50°47'2″ = 0.88663471123 rad
Angle ∠ C = γ = 98.11875053723° = 98°7'3″ = 1.71224735226 rad

Height: ha = 17.82196501244
Height: hb = 11.88797667496
Height: hc = 9.29772087605

Median: ma = 19.76110728454
Median: mb = 15.98443673631
Median: mc = 10.08771205009

Inradius: r = 4.0354637764
Circumradius: R = 11.61663896909

Vertex coordinates: A[23; 0] B[0; 0] C[7.58769565217; 9.29772087605]
Centroid: CG[10.19656521739; 3.09990695868]
Coordinates of the circumscribed circle: U[11.5; -1.6440277248]
Coordinates of the inscribed circle: I[8.5; 4.0354637764]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 148.9011454089° = 148°54'5″ = 0.54327720187 rad
∠ B' = β' = 129.2166051283° = 129°12'58″ = 0.88663471123 rad
∠ C' = γ' = 81.88224946277° = 81°52'57″ = 1.71224735226 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.