# Triangle calculator SSS - result

Please enter the triangle sides:

### Acute isosceles triangle.

Sides: a = 3   b = 13   c = 13

Area: T = 19.37697573552
Perimeter: p = 29
Semiperimeter: s = 14.5

Angle ∠ A = α = 13.25216191296° = 13°15'6″ = 0.2311284385 rad
Angle ∠ B = β = 83.37441904352° = 83°22'27″ = 1.45551541343 rad
Angle ∠ C = γ = 83.37441904352° = 83°22'27″ = 1.45551541343 rad

Height: ha = 12.91331715701
Height: hb = 2.987996267
Height: hc = 2.987996267

Median: ma = 12.91331715701
Median: mb = 6.83773971656
Median: mc = 6.83773971656

Inradius: r = 1.33658453348
Circumradius: R = 6.5443706133

Vertex coordinates: A[13; 0] B[0; 0] C[0.34661538462; 2.987996267]
Centroid: CG[4.44987179487; 0.993332089]
Coordinates of the circumscribed circle: U[6.5; 0.75550430153]
Coordinates of the inscribed circle: I[1.5; 1.33658453348]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 166.748838087° = 166°44'54″ = 0.2311284385 rad
∠ B' = β' = 96.62658095648° = 96°37'33″ = 1.45551541343 rad
∠ C' = γ' = 96.62658095648° = 96°37'33″ = 1.45551541343 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    