# 16 17 28 triangle

### Obtuse scalene triangle.

Sides: a = 16   b = 17   c = 28

Area: T = 122.17217541
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 30.8865674594° = 30°53'8″ = 0.53990567134 rad
Angle ∠ B = β = 33.05326598356° = 33°3'10″ = 0.57768777407 rad
Angle ∠ C = γ = 116.062166557° = 116°3'42″ = 2.02656581996 rad

Height: ha = 15.27114692626
Height: hb = 14.37331475412
Height: hc = 8.72765538643

Median: ma = 21.73770651193
Median: mb = 21.16601039695
Median: mc = 8.74664278423

Inradius: r = 4.0065631282
Circumradius: R = 15.58546170338

Vertex coordinates: A[28; 0] B[0; 0] C[13.41107142857; 8.72765538643]
Centroid: CG[13.80435714286; 2.90988512881]
Coordinates of the circumscribed circle: U[14; -6.84769181453]
Coordinates of the inscribed circle: I[13.5; 4.0065631282]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.1144325406° = 149°6'52″ = 0.53990567134 rad
∠ B' = β' = 146.9477340164° = 146°56'50″ = 0.57768777407 rad
∠ C' = γ' = 63.93883344296° = 63°56'18″ = 2.02656581996 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    