# 12 12 23 triangle

### Obtuse isosceles triangle.

Sides: a = 12   b = 12   c = 23

Area: T = 39.42200139523
Perimeter: p = 47
Semiperimeter: s = 23.5

Angle ∠ A = α = 16.59878421359° = 16°35'52″ = 0.2989686994 rad
Angle ∠ B = β = 16.59878421359° = 16°35'52″ = 0.2989686994 rad
Angle ∠ C = γ = 146.8044315728° = 146°48'16″ = 2.56222186656 rad

Height: ha = 6.57700023254
Height: hb = 6.57700023254
Height: hc = 3.42878273002

Median: ma = 17.33549358234
Median: mb = 17.33549358234
Median: mc = 3.42878273002

Inradius: r = 1.67774474022
Circumradius: R = 21.00545587757

Vertex coordinates: A[23; 0] B[0; 0] C[11.5; 3.42878273002]
Centroid: CG[11.5; 1.14326091001]
Coordinates of the circumscribed circle: U[11.5; -17.57767314755]
Coordinates of the inscribed circle: I[11.5; 1.67774474022]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 163.4022157864° = 163°24'8″ = 0.2989686994 rad
∠ B' = β' = 163.4022157864° = 163°24'8″ = 0.2989686994 rad
∠ C' = γ' = 33.19656842717° = 33°11'44″ = 2.56222186656 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.