# 3 18 19 triangle

### Obtuse scalene triangle.

Sides: a = 3   b = 18   c = 19

Area: T = 26.07768096208
Perimeter: p = 40
Semiperimeter: s = 20

Angle ∠ A = α = 8.77215990616° = 8°46'18″ = 0.15330932843 rad
Angle ∠ B = β = 66.20222871793° = 66°12'8″ = 1.15554478836 rad
Angle ∠ C = γ = 105.0266113759° = 105°1'34″ = 1.83330514857 rad

Height: ha = 17.38545397472
Height: hb = 2.89774232912
Height: hc = 2.74549273285

Median: ma = 18.44658667457
Median: mb = 10.19880390272
Median: mc = 8.73221245983

Inradius: r = 1.3043840481
Circumradius: R = 9.8366325982

Vertex coordinates: A[19; 0] B[0; 0] C[1.21105263158; 2.74549273285]
Centroid: CG[6.73768421053; 0.91549757762]
Coordinates of the circumscribed circle: U[9.5; -2.55501585879]
Coordinates of the inscribed circle: I[2; 1.3043840481]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 171.2288400938° = 171°13'42″ = 0.15330932843 rad
∠ B' = β' = 113.7987712821° = 113°47'52″ = 1.15554478836 rad
∠ C' = γ' = 74.97438862409° = 74°58'26″ = 1.83330514857 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.