# 12 12 19 triangle

### Obtuse isosceles triangle.

Sides: a = 12   b = 12   c = 19

Area: T = 69.64986719184
Perimeter: p = 43
Semiperimeter: s = 21.5

Angle ∠ A = α = 37.65884620062° = 37°39'30″ = 0.65772641532 rad
Angle ∠ B = β = 37.65884620062° = 37°39'30″ = 0.65772641532 rad
Angle ∠ C = γ = 104.6833075988° = 104°40'59″ = 1.82770643471 rad

Height: ha = 11.60881119864
Height: hb = 11.60881119864
Height: hc = 7.33114391493

Median: ma = 14.71439389696
Median: mb = 14.71439389696
Median: mc = 7.33114391493

Inradius: r = 3.23994731125
Circumradius: R = 9.82107184884

Vertex coordinates: A[19; 0] B[0; 0] C[9.5; 7.33114391493]
Centroid: CG[9.5; 2.44438130498]
Coordinates of the circumscribed circle: U[9.5; -2.48992793391]
Coordinates of the inscribed circle: I[9.5; 3.23994731125]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.3421537994° = 142°20'30″ = 0.65772641532 rad
∠ B' = β' = 142.3421537994° = 142°20'30″ = 0.65772641532 rad
∠ C' = γ' = 75.31769240124° = 75°19'1″ = 1.82770643471 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.