# 20 26 29 triangle

### Acute scalene triangle.

Sides: a = 20   b = 26   c = 29

Area: T = 253.275541827
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 42.20875410688° = 42°12'27″ = 0.73766605608 rad
Angle ∠ B = β = 60.85218854471° = 60°51'7″ = 1.06220657571 rad
Angle ∠ C = γ = 76.94105734841° = 76°56'26″ = 1.34328663357 rad

Height: ha = 25.3287541827
Height: hb = 19.48327244823
Height: hc = 17.46772702255

Median: ma = 25.66112548407
Median: mb = 21.24985293609
Median: mc = 18.10438669902

Inradius: r = 6.75440111539
Circumradius: R = 14.88549818342

Vertex coordinates: A[29; 0] B[0; 0] C[9.74113793103; 17.46772702255]
Centroid: CG[12.91437931034; 5.82224234085]
Coordinates of the circumscribed circle: U[14.5; 3.36334333952]
Coordinates of the inscribed circle: I[11.5; 6.75440111539]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.7922458931° = 137°47'33″ = 0.73766605608 rad
∠ B' = β' = 119.1488114553° = 119°8'53″ = 1.06220657571 rad
∠ C' = γ' = 103.0599426516° = 103°3'34″ = 1.34328663357 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    