# 15 15 27 triangle

### Obtuse isosceles triangle.

Sides: a = 15   b = 15   c = 27

Area: T = 88.26877036067
Perimeter: p = 57
Semiperimeter: s = 28.5

Angle ∠ A = α = 25.84219327632° = 25°50'31″ = 0.45110268118 rad
Angle ∠ B = β = 25.84219327632° = 25°50'31″ = 0.45110268118 rad
Angle ∠ C = γ = 128.3166134474° = 128°18'58″ = 2.243953903 rad

Height: ha = 11.76990271476
Height: hb = 11.76990271476
Height: hc = 6.53883484153

Median: ma = 20.51221914968
Median: mb = 20.51221914968
Median: mc = 6.53883484153

Inradius: r = 3.09771124073
Circumradius: R = 17.20661800403

Vertex coordinates: A[27; 0] B[0; 0] C[13.5; 6.53883484153]
Centroid: CG[13.5; 2.17994494718]
Coordinates of the circumscribed circle: U[13.5; -10.6687831625]
Coordinates of the inscribed circle: I[13.5; 3.09771124073]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.1588067237° = 154°9'29″ = 0.45110268118 rad
∠ B' = β' = 154.1588067237° = 154°9'29″ = 0.45110268118 rad
∠ C' = γ' = 51.68438655263° = 51°41'2″ = 2.243953903 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.