# 18 21 22 triangle

### Acute scalene triangle.

Sides: a = 18   b = 21   c = 22

Area: T = 175.4599218909
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 49.42657513336° = 49°25'33″ = 0.8632642096 rad
Angle ∠ B = β = 62.39443231026° = 62°23'40″ = 1.08989863727 rad
Angle ∠ C = γ = 68.18799255638° = 68°10'48″ = 1.19899641849 rad

Height: ha = 19.49554687676
Height: hb = 16.71104018008
Height: hc = 15.95108380826

Median: ma = 19.53220249846
Median: mb = 17.1399136501
Median: mc = 16.17109616288

Inradius: r = 5.75327612757
Circumradius: R = 11.84989071873

Vertex coordinates: A[22; 0] B[0; 0] C[8.34109090909; 15.95108380826]
Centroid: CG[10.11436363636; 5.31769460275]
Coordinates of the circumscribed circle: U[11; 4.40441573011]
Coordinates of the inscribed circle: I[9.5; 5.75327612757]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.5744248666° = 130°34'27″ = 0.8632642096 rad
∠ B' = β' = 117.6065676897° = 117°36'20″ = 1.08989863727 rad
∠ C' = γ' = 111.8220074436° = 111°49'12″ = 1.19899641849 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.