21 26 28 triangle

Acute scalene triangle.

Sides: a = 21   b = 26   c = 28

Area: T = 259.9976995175
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 45.5844015584° = 45°35'2″ = 0.79655911582 rad
Angle ∠ B = β = 62.1710842728° = 62°10'15″ = 1.08550859043 rad
Angle ∠ C = γ = 72.24551416879° = 72°14'43″ = 1.2610915591 rad

Height: ha = 24.76216185881
Height: hb = 209.9997688596
Height: hc = 18.57112139411

Median: ma = 24.8954778569
Median: mb = 21.05994396887
Median: mc = 19.03994327647

Vertex coordinates: A[28; 0] B[0; 0] C[9.80435714286; 18.57112139411]
Centroid: CG[12.60111904762; 6.1990404647]
Coordinates of the circumscribed circle: U[14; 4.48327441149]
Coordinates of the inscribed circle: I[11.5; 6.93332532047]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 134.4165984416° = 134°24'58″ = 0.79655911582 rad
∠ B' = β' = 117.8299157272° = 117°49'45″ = 1.08550859043 rad
∠ C' = γ' = 107.7554858312° = 107°45'17″ = 1.2610915591 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    