# Triangle calculator SSS - result

Please enter the triangle sides:

### Acute scalene triangle.

Sides: a = 17   b = 18   c = 20

Area: T = 143.4344436242
Perimeter: p = 55
Semiperimeter: s = 27.5

Angle ∠ A = α = 52.8311100344° = 52°49'52″ = 0.92220766485 rad
Angle ∠ B = β = 57.53663312514° = 57°32'11″ = 1.00441984199 rad
Angle ∠ C = γ = 69.63325684046° = 69°37'57″ = 1.21553175853 rad

Height: ha = 16.87546395579
Height: hb = 15.93771595824
Height: hc = 14.34334436242

Median: ma = 17.02220445305
Median: mb = 16.23326830807
Median: mc = 14.37701078632

Inradius: r = 5.21657976815
Circumradius: R = 10.66768945066

Vertex coordinates: A[20; 0] B[0; 0] C[9.125; 14.34334436242]
Centroid: CG[9.70883333333; 4.78111478747]
Coordinates of the circumscribed circle: U[10; 3.71224975979]
Coordinates of the inscribed circle: I[9.5; 5.21657976815]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 127.1698899656° = 127°10'8″ = 0.92220766485 rad
∠ B' = β' = 122.4643668749° = 122°27'49″ = 1.00441984199 rad
∠ C' = γ' = 110.3677431595° = 110°22'3″ = 1.21553175853 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   