# 15 15 23 triangle

### Obtuse isosceles triangle.

Sides: a = 15   b = 15   c = 23

Area: T = 110.7532821634
Perimeter: p = 53
Semiperimeter: s = 26.5

Angle ∠ A = α = 39.94545051898° = 39°56'40″ = 0.69771631336 rad
Angle ∠ B = β = 39.94545051898° = 39°56'40″ = 0.69771631336 rad
Angle ∠ C = γ = 100.111098962° = 100°6'40″ = 1.74772663863 rad

Height: ha = 14.76770428846
Height: hb = 14.76770428846
Height: hc = 9.63106801421

Median: ma = 17.90994946886
Median: mb = 17.90994946886
Median: mc = 9.63106801421

Inradius: r = 4.17993517598
Circumradius: R = 11.68114179622

Vertex coordinates: A[23; 0] B[0; 0] C[11.5; 9.63106801421]
Centroid: CG[11.5; 3.2110226714]
Coordinates of the circumscribed circle: U[11.5; -2.051073782]
Coordinates of the inscribed circle: I[11.5; 4.17993517598]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.055549481° = 140°3'20″ = 0.69771631336 rad
∠ B' = β' = 140.055549481° = 140°3'20″ = 0.69771631336 rad
∠ C' = γ' = 79.88990103796° = 79°53'20″ = 1.74772663863 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.