15 21 25 triangle

Acute scalene triangle.

Sides: a = 15   b = 21   c = 25

Area: T = 157.166611435
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 36.77988554827° = 36°46'44″ = 0.64219121233 rad
Angle ∠ B = β = 56.95325545924° = 56°57'9″ = 0.99440095951 rad
Angle ∠ C = γ = 86.26985899249° = 86°16'7″ = 1.50656709352 rad

Height: ha = 20.95554819134
Height: hb = 14.96882013667
Height: hc = 12.5733289148

Median: ma = 21.83546055609
Median: mb = 17.74111949992
Median: mc = 13.29547358003

Vertex coordinates: A[25; 0] B[0; 0] C[8.18; 12.5733289148]
Centroid: CG[11.06; 4.19110963827]
Coordinates of the circumscribed circle: U[12.5; 0.81552202562]
Coordinates of the inscribed circle: I[9.5; 5.15329873558]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.2211144517° = 143°13'16″ = 0.64219121233 rad
∠ B' = β' = 123.0477445408° = 123°2'51″ = 0.99440095951 rad
∠ C' = γ' = 93.73114100751° = 93°43'53″ = 1.50656709352 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    