# 18 21 23 triangle

### Acute scalene triangle.

Sides: a = 18   b = 21   c = 23

Area: T = 179.55550055
Perimeter: p = 62
Semiperimeter: s = 31

Angle ∠ A = α = 48.03303348284° = 48°1'49″ = 0.83882874836 rad
Angle ∠ B = β = 60.16596772223° = 60°9'35″ = 1.05499844445 rad
Angle ∠ C = γ = 71.81099879493° = 71°48'36″ = 1.25333207255 rad

Height: ha = 19.95105561666
Height: hb = 17.11004767143
Height: hc = 15.61334787391

Median: ma = 20.10997512422
Median: mb = 17.78334192438
Median: mc = 15.81992920196

Inradius: r = 5.79220969516
Circumradius: R = 12.10549256965

Vertex coordinates: A[23; 0] B[0; 0] C[8.95765217391; 15.61334787391]
Centroid: CG[10.6522173913; 5.2044492913]
Coordinates of the circumscribed circle: U[11.5; 3.77987863285]
Coordinates of the inscribed circle: I[10; 5.79220969516]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 131.9769665172° = 131°58'11″ = 0.83882874836 rad
∠ B' = β' = 119.8440322778° = 119°50'25″ = 1.05499844445 rad
∠ C' = γ' = 108.1990012051° = 108°11'24″ = 1.25333207255 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.