# 9 13 17 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 13   c = 17

Area: T = 57.68217778852
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 31.46769762933° = 31°28'1″ = 0.5499202342 rad
Angle ∠ B = β = 48.93989554799° = 48°56'20″ = 0.85441459056 rad
Angle ∠ C = γ = 99.59440682269° = 99°35'39″ = 1.7388244406 rad

Height: ha = 12.81881728634
Height: hb = 8.87441196746
Height: hc = 6.78660915159

Median: ma = 14.44881832768
Median: mb = 11.94878031453
Median: mc = 7.26329195232

Inradius: r = 2.95880398915
Circumradius: R = 8.62105733982

Vertex coordinates: A[17; 0] B[0; 0] C[5.91217647059; 6.78660915159]
Centroid: CG[7.6377254902; 2.26220305053]
Coordinates of the circumscribed circle: U[8.5; -1.4376762233]
Coordinates of the inscribed circle: I[6.5; 2.95880398915]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 148.5333023707° = 148°31'59″ = 0.5499202342 rad
∠ B' = β' = 131.061104452° = 131°3'40″ = 0.85441459056 rad
∠ C' = γ' = 80.40659317731° = 80°24'21″ = 1.7388244406 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.