# Triangle calculator SSS - result

Please enter the triangle sides:

### Acute isosceles triangle.

Sides: a = 17   b = 17   c = 20

Area: T = 137.4777270849
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 53.96881209275° = 53°58'5″ = 0.94219214013 rad
Angle ∠ B = β = 53.96881209275° = 53°58'5″ = 0.94219214013 rad
Angle ∠ C = γ = 72.06437581449° = 72°3'50″ = 1.2587749851 rad

Height: ha = 16.17437965704
Height: hb = 16.17437965704
Height: hc = 13.74877270849

Median: ma = 16.5
Median: mb = 16.5
Median: mc = 13.74877270849

Inradius: r = 5.09217507722
Circumradius: R = 10.51108283797

Vertex coordinates: A[20; 0] B[0; 0] C[10; 13.74877270849]
Centroid: CG[10; 4.5832575695]
Coordinates of the circumscribed circle: U[10; 3.23768987052]
Coordinates of the inscribed circle: I[10; 5.09217507722]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 126.0321879072° = 126°1'55″ = 0.94219214013 rad
∠ B' = β' = 126.0321879072° = 126°1'55″ = 0.94219214013 rad
∠ C' = γ' = 107.9366241855° = 107°56'10″ = 1.2587749851 rad

# How did we calculate this triangle?

### 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    