# 7 9 13 triangle

### Obtuse scalene triangle.

Sides: a = 7   b = 9   c = 13

Area: T = 29.95330883216
Perimeter: p = 29
Semiperimeter: s = 14.5

Angle ∠ A = α = 30.79883817103° = 30°47'54″ = 0.53875331651 rad
Angle ∠ B = β = 41.17110828964° = 41°10'16″ = 0.71985709532 rad
Angle ∠ C = γ = 108.0310535393° = 108°1'50″ = 1.88554885353 rad

Height: ha = 8.55880252347
Height: hb = 6.65662418492
Height: hc = 4.60881674341

Median: ma = 10.61883802908
Median: mb = 9.42107218407
Median: mc = 4.77696960071

Inradius: r = 2.06657302291
Circumradius: R = 6.83656891217

Vertex coordinates: A[13; 0] B[0; 0] C[5.26992307692; 4.60881674341]
Centroid: CG[6.09897435897; 1.53660558114]
Coordinates of the circumscribed circle: U[6.5; -2.11658085377]
Coordinates of the inscribed circle: I[5.5; 2.06657302291]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.202161829° = 149°12'6″ = 0.53875331651 rad
∠ B' = β' = 138.8298917104° = 138°49'44″ = 0.71985709532 rad
∠ C' = γ' = 71.96994646067° = 71°58'10″ = 1.88554885353 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.