# 17 21 30 triangle

### Obtuse scalene triangle.

Sides: a = 17   b = 21   c = 30

Area: T = 173.3676663462
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 33.39224249359° = 33°23'33″ = 0.58328077604 rad
Angle ∠ B = β = 42.83334280661° = 42°50' = 0.74875843497 rad
Angle ∠ C = γ = 103.7744146998° = 103°46'27″ = 1.81112005436 rad

Height: ha = 20.39660780544
Height: hb = 16.51111108059
Height: hc = 11.55877775641

Median: ma = 24.45991496173
Median: mb = 22.00656810847
Median: mc = 11.83221595662

Inradius: r = 5.09990195136
Circumradius: R = 15.44441456421

Vertex coordinates: A[30; 0] B[0; 0] C[12.46766666667; 11.55877775641]
Centroid: CG[14.15655555556; 3.85325925214]
Coordinates of the circumscribed circle: U[15; -3.67771775338]
Coordinates of the inscribed circle: I[13; 5.09990195136]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.6087575064° = 146°36'27″ = 0.58328077604 rad
∠ B' = β' = 137.1676571934° = 137°10' = 0.74875843497 rad
∠ C' = γ' = 76.2265853002° = 76°13'33″ = 1.81112005436 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.