# 28 29 30 triangle

### Acute scalene triangle.

Sides: a = 28   b = 29   c = 30

Area: T = 363.2976624675
Perimeter: p = 87
Semiperimeter: s = 43.5

Angle ∠ A = α = 56.63329870308° = 56°37'59″ = 0.98884320889 rad
Angle ∠ B = β = 59.88217876035° = 59°52'54″ = 1.04551343557 rad
Angle ∠ C = γ = 63.48552253657° = 63°29'7″ = 1.1088026209 rad

Height: ha = 25.95497589053
Height: hb = 25.05549396327
Height: hc = 24.22197749783

Median: ma = 25.97111378264
Median: mb = 25.13546374551
Median: mc = 24.23883992871

Inradius: r = 8.35216465442
Circumradius: R = 16.76331615225

Vertex coordinates: A[30; 0] B[0; 0] C[14.05; 24.22197749783]
Centroid: CG[14.68333333333; 8.07332583261]
Coordinates of the circumscribed circle: U[15; 7.48435542511]
Coordinates of the inscribed circle: I[14.5; 8.35216465442]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 123.3677012969° = 123°22'1″ = 0.98884320889 rad
∠ B' = β' = 120.1188212397° = 120°7'6″ = 1.04551343557 rad
∠ C' = γ' = 116.5154774634° = 116°30'53″ = 1.1088026209 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    