# 18 23 28 triangle

### Acute scalene triangle.

Sides: a = 18   b = 23   c = 28

Area: T = 206.2879997818
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 39.83881498056° = 39°50'17″ = 0.6955306882 rad
Angle ∠ B = β = 54.94220420416° = 54°56'31″ = 0.95989195314 rad
Angle ∠ C = γ = 85.22198081528° = 85°13'11″ = 1.48773662402 rad

Height: ha = 22.92199997576
Height: hb = 17.93773911147
Height: hc = 14.73442855585

Median: ma = 23.99895810718
Median: mb = 20.53765527779
Median: mc = 15.18222264507

Inradius: r = 5.97991303716
Circumradius: R = 14.04988657681

Vertex coordinates: A[28; 0] B[0; 0] C[10.33992857143; 14.73442855585]
Centroid: CG[12.78797619048; 4.91114285195]
Coordinates of the circumscribed circle: U[14; 1.1710738814]
Coordinates of the inscribed circle: I[11.5; 5.97991303716]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.1621850194° = 140°9'43″ = 0.6955306882 rad
∠ B' = β' = 125.0587957958° = 125°3'29″ = 0.95989195314 rad
∠ C' = γ' = 94.78801918472° = 94°46'49″ = 1.48773662402 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.