# 8 8 13 triangle

### Obtuse isosceles triangle.

Sides: a = 8   b = 8   c = 13

Area: T = 30.31439819225
Perimeter: p = 29
Semiperimeter: s = 14.5

Angle ∠ A = α = 35.65990876961° = 35°39'33″ = 0.62223684886 rad
Angle ∠ B = β = 35.65990876961° = 35°39'33″ = 0.62223684886 rad
Angle ∠ C = γ = 108.6821824608° = 108°40'55″ = 1.89768556765 rad

Height: ha = 7.57884954806
Height: hb = 7.57884954806
Height: hc = 4.66436895265

Median: ma = 10.02549688279
Median: mb = 10.02549688279
Median: mc = 4.66436895265

Inradius: r = 2.09106194429
Circumradius: R = 6.8621520223

Vertex coordinates: A[13; 0] B[0; 0] C[6.5; 4.66436895265]
Centroid: CG[6.5; 1.55545631755]
Coordinates of the circumscribed circle: U[6.5; -2.19878306964]
Coordinates of the inscribed circle: I[6.5; 2.09106194429]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 144.3410912304° = 144°20'27″ = 0.62223684886 rad
∠ B' = β' = 144.3410912304° = 144°20'27″ = 0.62223684886 rad
∠ C' = γ' = 71.31881753923° = 71°19'5″ = 1.89768556765 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.