# 18 25 26 triangle

### Acute scalene triangle.

Sides: a = 18   b = 25   c = 26

Area: T = 214.399901469
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 41.27661795162° = 41°16'34″ = 0.72204052352 rad
Angle ∠ B = β = 66.38217417975° = 66°22'54″ = 1.15985799576 rad
Angle ∠ C = γ = 72.34220786863° = 72°20'31″ = 1.26326074608 rad

Height: ha = 23.82221127433
Height: hb = 17.15219211752
Height: hc = 16.49222318992

Median: ma = 23.86441991276
Median: mb = 18.54404962177
Median: mc = 17.47985582929

Inradius: r = 6.21444641939
Circumradius: R = 13.64327865782

Vertex coordinates: A[26; 0] B[0; 0] C[7.21215384615; 16.49222318992]
Centroid: CG[11.07105128205; 5.49774106331]
Coordinates of the circumscribed circle: U[13; 4.13883119287]
Coordinates of the inscribed circle: I[9.5; 6.21444641939]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.7243820484° = 138°43'26″ = 0.72204052352 rad
∠ B' = β' = 113.6188258203° = 113°37'6″ = 1.15985799576 rad
∠ C' = γ' = 107.6587921314° = 107°39'29″ = 1.26326074608 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.