4 15 18 triangle

Obtuse scalene triangle.

Sides: a = 4   b = 15   c = 18

Area: T = 21.66765064097
Perimeter: p = 37
Semiperimeter: s = 18.5

Angle ∠ A = α = 9.23554919597° = 9°14'8″ = 0.16111897427 rad
Angle ∠ B = β = 37.00223228374° = 37°8″ = 0.64658123644 rad
Angle ∠ C = γ = 133.7622185203° = 133°45'44″ = 2.33545905465 rad

Height: ha = 10.83332532048
Height: hb = 2.88988675213
Height: hc = 2.40773896011

Median: ma = 16.44768842034
Median: mb = 10.66553645039
Median: mc = 6.2854902545

Vertex coordinates: A[18; 0] B[0; 0] C[3.19444444444; 2.40773896011]
Centroid: CG[7.06548148148; 0.80224632004]
Coordinates of the circumscribed circle: U[9; -8.61992945216]
Coordinates of the inscribed circle: I[3.5; 1.17111625086]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 170.765450804° = 170°45'52″ = 0.16111897427 rad
∠ B' = β' = 142.9987677163° = 142°59'52″ = 0.64658123644 rad
∠ C' = γ' = 46.23878147971° = 46°14'16″ = 2.33545905465 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    