# Triangle calculator SSS - result

Please enter the triangle sides:

### Acute scalene triangle.

Sides: a = 13   b = 17   c = 18

Area: T = 105.3299572649
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 43.4990358347° = 43°29'25″ = 0.7599049946 rad
Angle ∠ B = β = 64.15875871263° = 64°9'27″ = 1.12197611355 rad
Angle ∠ C = γ = 72.35220545267° = 72°21'7″ = 1.26327815721 rad

Height: ha = 16.21999342536
Height: hb = 12.38881850175
Height: hc = 11.76999525165

Median: ma = 16.2565768207
Median: mb = 13.22003787824
Median: mc = 12.16655250606

Inradius: r = 4.38774821937
Circumradius: R = 9.44444827741

Vertex coordinates: A[18; 0] B[0; 0] C[5.66766666667; 11.76999525165]
Centroid: CG[7.88988888889; 3.98999841722]
Coordinates of the circumscribed circle: U[9; 2.86332594835]
Coordinates of the inscribed circle: I[7; 4.38774821937]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 136.5109641653° = 136°30'35″ = 0.7599049946 rad
∠ B' = β' = 115.8422412874° = 115°50'33″ = 1.12197611355 rad
∠ C' = γ' = 107.6487945473° = 107°38'53″ = 1.26327815721 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   