# 10 16 20 triangle

### Obtuse scalene triangle.

Sides: a = 10   b = 16   c = 20

Area: T = 79.24401413426
Perimeter: p = 46
Semiperimeter: s = 23

Angle ∠ A = α = 29.68662952314° = 29°41'11″ = 0.51881235945 rad
Angle ∠ B = β = 52.41104970351° = 52°24'38″ = 0.91547357359 rad
Angle ∠ C = γ = 97.90332077335° = 97°54'12″ = 1.70987333232 rad

Height: ha = 15.84880282685
Height: hb = 9.90550176678
Height: hc = 7.92440141343

Median: ma = 17.40768951855
Median: mb = 13.6388181697
Median: mc = 8.83217608663

Vertex coordinates: A[20; 0] B[0; 0] C[6.1; 7.92440141343]
Centroid: CG[8.7; 2.64113380448]
Coordinates of the circumscribed circle: U[10; -1.38881853078]
Coordinates of the inscribed circle: I[7; 3.44552235366]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 150.3143704769° = 150°18'49″ = 0.51881235945 rad
∠ B' = β' = 127.5989502965° = 127°35'22″ = 0.91547357359 rad
∠ C' = γ' = 82.09767922665° = 82°5'48″ = 1.70987333232 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    