# 9 15 22 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 15   c = 22

Area: T = 50.75443101618
Perimeter: p = 46
Semiperimeter: s = 23

Angle ∠ A = α = 17.91547679103° = 17°54'53″ = 0.31326716848 rad
Angle ∠ B = β = 30.84218279549° = 30°50'31″ = 0.53882914451 rad
Angle ∠ C = γ = 131.2433404135° = 131°14'36″ = 2.29106295237 rad

Height: ha = 11.27987355915
Height: hb = 6.76772413549
Height: hc = 4.61440281965

Median: ma = 18.28325052988
Median: mb = 15.04216089565
Median: mc = 5.65768542495

Inradius: r = 2.20767091375
Circumradius: R = 14.62992994158

Vertex coordinates: A[22; 0] B[0; 0] C[7.72772727273; 4.61440281965]
Centroid: CG[9.90990909091; 1.53880093988]
Coordinates of the circumscribed circle: U[11; -9.64545010964]
Coordinates of the inscribed circle: I[8; 2.20767091375]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.085523209° = 162°5'7″ = 0.31326716848 rad
∠ B' = β' = 149.1588172045° = 149°9'29″ = 0.53882914451 rad
∠ C' = γ' = 48.75765958652° = 48°45'24″ = 2.29106295237 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    