# 17 26 30 triangle

### Acute scalene triangle.

Sides: a = 17   b = 26   c = 30

Area: T = 220.4021763831
Perimeter: p = 73
Semiperimeter: s = 36.5

Angle ∠ A = α = 34.41215086698° = 34°24'41″ = 0.60105941269 rad
Angle ∠ B = β = 59.80552218091° = 59°48'19″ = 1.04437980305 rad
Angle ∠ C = γ = 85.78332695211° = 85°47' = 1.49772004963 rad

Height: ha = 25.93296192743
Height: hb = 16.95439818332
Height: hc = 14.69334509221

Median: ma = 26.75435044433
Median: mb = 20.62876513447
Median: mc = 16.04768065359

Inradius: r = 6.03884044885
Circumradius: R = 15.04107144769

Vertex coordinates: A[30; 0] B[0; 0] C[8.55; 14.69334509221]
Centroid: CG[12.85; 4.8987816974]
Coordinates of the circumscribed circle: U[15; 1.1065934888]
Coordinates of the inscribed circle: I[10.5; 6.03884044885]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.588849133° = 145°35'19″ = 0.60105941269 rad
∠ B' = β' = 120.1954778191° = 120°11'41″ = 1.04437980305 rad
∠ C' = γ' = 94.21767304789° = 94°13' = 1.49772004963 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    