# 25 28 30 triangle

### Acute scalene triangle.

Sides: a = 25   b = 28   c = 30

Area: T = 326.0488213459
Perimeter: p = 83
Semiperimeter: s = 41.5

Angle ∠ A = α = 50.92435231941° = 50°55'25″ = 0.88987831465 rad
Angle ∠ B = β = 60.39661691983° = 60°23'46″ = 1.05441120081 rad
Angle ∠ C = γ = 68.68803076076° = 68°40'49″ = 1.1998697499 rad

Height: ha = 26.08438570767
Height: hb = 23.28991581042
Height: hc = 21.7376547564

Median: ma = 26.18768287503
Median: mb = 23.80112604708
Median: mc = 21.89774884405

Inradius: r = 7.85765834569
Circumradius: R = 16.10219131014

Vertex coordinates: A[30; 0] B[0; 0] C[12.35; 21.7376547564]
Centroid: CG[14.11766666667; 7.24655158547]
Coordinates of the circumscribed circle: U[15; 5.8544195549]
Coordinates of the inscribed circle: I[13.5; 7.85765834569]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 129.0766476806° = 129°4'35″ = 0.88987831465 rad
∠ B' = β' = 119.6043830802° = 119°36'14″ = 1.05441120081 rad
∠ C' = γ' = 111.3219692392° = 111°19'11″ = 1.1998697499 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    