# 4 14 15 triangle

### Obtuse scalene triangle.

Sides: a = 4   b = 14   c = 15

Area: T = 27.81107443266
Perimeter: p = 33
Semiperimeter: s = 16.5

Angle ∠ A = α = 15.35988855808° = 15°21'32″ = 0.26880631228 rad
Angle ∠ B = β = 67.9765687163° = 67°58'32″ = 1.18663995523 rad
Angle ∠ C = γ = 96.66554272562° = 96°39'56″ = 1.68771299785 rad

Height: ha = 13.90553721633
Height: hb = 3.97329634752
Height: hc = 3.70880992435

Median: ma = 14.37701078632
Median: mb = 8.45657672626
Median: mc = 7.05333679898

Inradius: r = 1.68554996562
Circumradius: R = 7.55110384596

Vertex coordinates: A[15; 0] B[0; 0] C[1.5; 3.70880992435]
Centroid: CG[5.5; 1.23660330812]
Coordinates of the circumscribed circle: U[7.5; -0.87664598212]
Coordinates of the inscribed circle: I[2.5; 1.68554996562]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 164.6411114419° = 164°38'28″ = 0.26880631228 rad
∠ B' = β' = 112.0244312837° = 112°1'28″ = 1.18663995523 rad
∠ C' = γ' = 83.33545727438° = 83°20'4″ = 1.68771299785 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    