# 7 14 18 triangle

### Obtuse scalene triangle.

Sides: a = 7   b = 14   c = 18

Area: T = 44.84334777866
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 20.84986512302° = 20°50'55″ = 0.36438776086 rad
Angle ∠ B = β = 45.38216583472° = 45°22'54″ = 0.79220593582 rad
Angle ∠ C = γ = 113.7769690423° = 113°46'11″ = 1.98656556869 rad

Height: ha = 12.81224222248
Height: hb = 6.40662111124
Height: hc = 4.9832608643

Median: ma = 15.74400762387
Median: mb = 11.72660393996
Median: mc = 6.44220493634

Inradius: r = 2.32996655275
Circumradius: R = 9.83442060377

Vertex coordinates: A[18; 0] B[0; 0] C[4.91766666667; 4.9832608643]
Centroid: CG[7.63988888889; 1.66108695477]
Coordinates of the circumscribed circle: U[9; -3.96437871274]
Coordinates of the inscribed circle: I[5.5; 2.32996655275]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 159.151134877° = 159°9'5″ = 0.36438776086 rad
∠ B' = β' = 134.6188341653° = 134°37'6″ = 0.79220593582 rad
∠ C' = γ' = 66.23303095773° = 66°13'49″ = 1.98656556869 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.