# 12 18 19 triangle

### Acute scalene triangle.

Sides: a = 12   b = 18   c = 19

Area: T = 104.6354781502
Perimeter: p = 49
Semiperimeter: s = 24.5

Angle ∠ A = α = 37.72769622912° = 37°43'37″ = 0.65884597088 rad
Angle ∠ B = β = 66.61436132504° = 66°36'49″ = 1.16326268779 rad
Angle ∠ C = γ = 75.65994244584° = 75°39'34″ = 1.3210506067 rad

Height: ha = 17.43991302504
Height: hb = 11.62660868336
Height: hc = 11.01441875265

Median: ma = 17.50771414
Median: mb = 13.09658008537
Median: mc = 11.99895788083

Inradius: r = 4.27108074083
Circumradius: R = 9.80655348831

Vertex coordinates: A[19; 0] B[0; 0] C[4.76331578947; 11.01441875265]
Centroid: CG[7.92110526316; 3.67113958422]
Coordinates of the circumscribed circle: U[9.5; 2.42986857233]
Coordinates of the inscribed circle: I[6.5; 4.27108074083]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 142.2733037709° = 142°16'23″ = 0.65884597088 rad
∠ B' = β' = 113.386638675° = 113°23'11″ = 1.16326268779 rad
∠ C' = γ' = 104.3410575542° = 104°20'26″ = 1.3210506067 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.