# 15.5 12.7 3.2 triangle

### Obtuse scalene triangle.

Sides: a = 15.5   b = 12.7   c = 3.2

Area: T = 10.85112672071
Perimeter: p = 31.4
Semiperimeter: s = 15.7

Angle ∠ A = α = 147.7232589398° = 147°43'21″ = 2.57882455646 rad
Angle ∠ B = β = 25.94877355847° = 25°56'52″ = 0.45328734194 rad
Angle ∠ C = γ = 6.33296750172° = 6°19'47″ = 0.11104736696 rad

Height: ha = 1.44001635106
Height: hb = 1.70988609775
Height: hc = 6.78220420044

Median: ma = 5.07697633081
Median: mb = 9.21553404712
Median: mc = 14.0798707327

Inradius: r = 0.69111635164
Circumradius: R = 14.51325907412

Vertex coordinates: A[3.2; 0] B[0; 0] C[13.93875; 6.78220420044]
Centroid: CG[5.71325; 2.26106806681]
Coordinates of the circumscribed circle: U[1.6; 14.42441218111]
Coordinates of the inscribed circle: I[3; 0.69111635164]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 32.27774106019° = 32°16'39″ = 2.57882455646 rad
∠ B' = β' = 154.0522264415° = 154°3'8″ = 0.45328734194 rad
∠ C' = γ' = 173.6770324983° = 173°40'13″ = 0.11104736696 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    