# 12 13 23 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 13   c = 23

Area: T = 56.28549891179
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 22.1166323917° = 22°6'59″ = 0.38660026708 rad
Angle ∠ B = β = 24.07106146226° = 24°4'14″ = 0.42201114781 rad
Angle ∠ C = γ = 133.813306146° = 133°48'47″ = 2.33554785047 rad

Height: ha = 9.38108315196
Height: hb = 8.65992290951
Height: hc = 4.89443468798

Median: ma = 17.6921806013
Median: mb = 17.15437167984
Median: mc = 4.92444289009

Inradius: r = 2.34552078799
Circumradius: R = 15.93767535476

Vertex coordinates: A[23; 0] B[0; 0] C[10.95765217391; 4.89443468798]
Centroid: CG[11.31988405797; 1.63114489599]
Coordinates of the circumscribed circle: U[11.5; -11.03331370714]
Coordinates of the inscribed circle: I[11; 2.34552078799]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 157.8843676083° = 157°53'1″ = 0.38660026708 rad
∠ B' = β' = 155.9299385377° = 155°55'46″ = 0.42201114781 rad
∠ C' = γ' = 46.18769385396° = 46°11'13″ = 2.33554785047 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.