# 13 13 17 triangle

### Acute isosceles triangle.

Sides: a = 13   b = 13   c = 17

Area: T = 83.60773411849
Perimeter: p = 43
Semiperimeter: s = 21.5

Angle ∠ A = α = 49.16877829725° = 49°10'4″ = 0.85881396988 rad
Angle ∠ B = β = 49.16877829725° = 49°10'4″ = 0.85881396988 rad
Angle ∠ C = γ = 81.66444340549° = 81°39'52″ = 1.4255313256 rad

Height: ha = 12.86326678746
Height: hb = 12.86326678746
Height: hc = 9.83661577865

Median: ma = 13.66656503687
Median: mb = 13.66656503687
Median: mc = 9.83661577865

Inradius: r = 3.88987135435
Circumradius: R = 8.59107527954

Vertex coordinates: A[17; 0] B[0; 0] C[8.5; 9.83661577865]
Centroid: CG[8.5; 3.27987192622]
Coordinates of the circumscribed circle: U[8.5; 1.2455404991]
Coordinates of the inscribed circle: I[8.5; 3.88987135435]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.8322217027° = 130°49'56″ = 0.85881396988 rad
∠ B' = β' = 130.8322217027° = 130°49'56″ = 0.85881396988 rad
∠ C' = γ' = 98.33655659451° = 98°20'8″ = 1.4255313256 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.