# 9 12 17 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 12   c = 17

Area: T = 51.57551878329
Perimeter: p = 38
Semiperimeter: s = 19

Angle ∠ A = α = 30.37437861998° = 30°22'26″ = 0.53301225755 rad
Angle ∠ B = β = 42.39109285431° = 42°23'27″ = 0.74398612761 rad
Angle ∠ C = γ = 107.2355285257° = 107°14'7″ = 1.87216088021 rad

Height: ha = 11.46111528518
Height: hb = 8.59658646388
Height: hc = 6.06876691568

Median: ma = 14.00989257261
Median: mb = 12.20765556157
Median: mc = 6.34442887702

Inradius: r = 2.71444835702
Circumradius: R = 8.98996282764

Vertex coordinates: A[17; 0] B[0; 0] C[6.64770588235; 6.06876691568]
Centroid: CG[7.88223529412; 2.02325563856]
Coordinates of the circumscribed circle: U[8.5; -2.63769268967]
Coordinates of the inscribed circle: I[7; 2.71444835702]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.62662138° = 149°37'34″ = 0.53301225755 rad
∠ B' = β' = 137.6099071457° = 137°36'33″ = 0.74398612761 rad
∠ C' = γ' = 72.76547147429° = 72°45'53″ = 1.87216088021 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.