9 12 15 triangle

Right scalene Pythagorean triangle.

Sides: a = 9   b = 12   c = 15

Area: T = 54
Perimeter: p = 36
Semiperimeter: s = 18

Angle ∠ A = α = 36.87698976458° = 36°52'12″ = 0.64435011088 rad
Angle ∠ B = β = 53.13301023542° = 53°7'48″ = 0.9277295218 rad
Angle ∠ C = γ = 90° = 1.57107963268 rad

Height: ha = 12
Height: hb = 9
Height: hc = 7.2

Median: ma = 12.8166005618
Median: mb = 10.81766538264
Median: mc = 7.5

Vertex coordinates: A[15; 0] B[0; 0] C[5.4; 7.2]
Centroid: CG[6.8; 2.4]
Coordinates of the circumscribed circle: U[7.5; 0]
Coordinates of the inscribed circle: I[6; 3]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.1330102354° = 143°7'48″ = 0.64435011088 rad
∠ B' = β' = 126.8769897646° = 126°52'12″ = 0.9277295218 rad
∠ C' = γ' = 90° = 1.57107963268 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    