# 11 11 13 triangle

### Acute isosceles triangle.

Sides: a = 11   b = 11   c = 13

Area: T = 57.68217778852
Perimeter: p = 35
Semiperimeter: s = 17.5

Angle ∠ A = α = 53.77884533802° = 53°46'42″ = 0.93986110781 rad
Angle ∠ B = β = 53.77884533802° = 53°46'42″ = 0.93986110781 rad
Angle ∠ C = γ = 72.44330932397° = 72°26'35″ = 1.26443704974 rad

Height: ha = 10.48875959791
Height: hb = 10.48875959791
Height: hc = 8.87441196746

Median: ma = 10.71221426428
Median: mb = 10.71221426428
Median: mc = 8.87441196746

Inradius: r = 3.29661015934
Circumradius: R = 6.81875776548

Vertex coordinates: A[13; 0] B[0; 0] C[6.5; 8.87441196746]
Centroid: CG[6.5; 2.95880398915]
Coordinates of the circumscribed circle: U[6.5; 2.05765420198]
Coordinates of the inscribed circle: I[6.5; 3.29661015934]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 126.222154662° = 126°13'18″ = 0.93986110781 rad
∠ B' = β' = 126.222154662° = 126°13'18″ = 0.93986110781 rad
∠ C' = γ' = 107.557690676° = 107°33'25″ = 1.26443704974 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.