# 16 18 20 triangle

### Acute scalene triangle.

Sides: a = 16   b = 18   c = 20

Area: T = 136.7888157382
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 49.45883981265° = 49°27'30″ = 0.86332118901 rad
Angle ∠ B = β = 58.75215587378° = 58°45'6″ = 1.02554081407 rad
Angle ∠ C = γ = 71.79900431357° = 71°47'24″ = 1.25329726229 rad

Height: ha = 17.09985196728
Height: hb = 15.19986841536
Height: hc = 13.67988157382

Median: ma = 17.26326765016
Median: mb = 15.71662336455
Median: mc = 13.78440487521

Inradius: r = 5.06662280512
Circumradius: R = 10.52772271194

Vertex coordinates: A[20; 0] B[0; 0] C[8.3; 13.67988157382]
Centroid: CG[9.43333333333; 4.56596052461]
Coordinates of the circumscribed circle: U[10; 3.29897584748]
Coordinates of the inscribed circle: I[9; 5.06662280512]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.5421601874° = 130°32'30″ = 0.86332118901 rad
∠ B' = β' = 121.2488441262° = 121°14'54″ = 1.02554081407 rad
∠ C' = γ' = 108.2109956864° = 108°12'36″ = 1.25329726229 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.