# 18 20 26 triangle

### Acute scalene triangle.

Sides: a = 18   b = 20   c = 26

Area: T = 179.6599554565
Perimeter: p = 64
Semiperimeter: s = 32

Angle ∠ A = α = 43.69108952793° = 43°41'27″ = 0.76325499758 rad
Angle ∠ B = β = 50.132165845° = 50°7'54″ = 0.87549624994 rad
Angle ∠ C = γ = 86.17774462707° = 86°10'39″ = 1.50440801784 rad

Height: ha = 19.95655060628
Height: hb = 17.96599554565
Height: hc = 13.81553503512

Median: ma = 21.37875583264
Median: mb = 20
Median: mc = 13.89224439894

Inradius: r = 5.61224860802
Circumradius: R = 13.02989855432

Vertex coordinates: A[26; 0] B[0; 0] C[11.53884615385; 13.81553503512]
Centroid: CG[12.51328205128; 4.60551167837]
Coordinates of the circumscribed circle: U[13; 0.86985990362]
Coordinates of the inscribed circle: I[12; 5.61224860802]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 136.3099104721° = 136°18'33″ = 0.76325499758 rad
∠ B' = β' = 129.868834155° = 129°52'6″ = 0.87549624994 rad
∠ C' = γ' = 93.82325537293° = 93°49'21″ = 1.50440801784 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.