# 15 16 25 triangle

### Obtuse scalene triangle.

Sides: a = 15   b = 16   c = 25

Area: T = 114.473270417
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 34.91552062474° = 34°54'55″ = 0.6099385308 rad
Angle ∠ B = β = 37.62771906288° = 37°37'38″ = 0.65767183647 rad
Angle ∠ C = γ = 107.4587603124° = 107°27'27″ = 1.87554889808 rad

Height: ha = 15.26330272227
Height: hb = 14.30990880213
Height: hc = 9.15878163336

Median: ma = 19.60222957839
Median: mb = 19
Median: mc = 9.17987798753

Inradius: r = 4.08883108632
Circumradius: R = 13.1043560459

Vertex coordinates: A[25; 0] B[0; 0] C[11.88; 9.15878163336]
Centroid: CG[12.29333333333; 3.05326054445]
Coordinates of the circumscribed circle: U[12.5; -3.93110681377]
Coordinates of the inscribed circle: I[12; 4.08883108632]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.0854793753° = 145°5'5″ = 0.6099385308 rad
∠ B' = β' = 142.3732809371° = 142°22'22″ = 0.65767183647 rad
∠ C' = γ' = 72.54223968763° = 72°32'33″ = 1.87554889808 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    