# 18 23 26 triangle

### Acute scalene triangle.

Sides: a = 18   b = 23   c = 26

Area: T = 202.2155077331
Perimeter: p = 67
Semiperimeter: s = 33.5

Angle ∠ A = α = 42.55655425086° = 42°33'20″ = 0.74327343317 rad
Angle ∠ B = β = 59.78877229044° = 59°47'16″ = 1.0433492617 rad
Angle ∠ C = γ = 77.6576734587° = 77°39'24″ = 1.35553657049 rad

Height: ha = 22.46883419257
Height: hb = 17.58439197679
Height: hc = 15.55550059485

Median: ma = 22.83663744933
Median: mb = 19.17768089108
Median: mc = 16.04768065359

Inradius: r = 6.03662709651
Circumradius: R = 13.30876130401

Vertex coordinates: A[26; 0] B[0; 0] C[9.05876923077; 15.55550059485]
Centroid: CG[11.68658974359; 5.18550019828]
Coordinates of the circumscribed circle: U[13; 2.84547433673]
Coordinates of the inscribed circle: I[10.5; 6.03662709651]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.4444457491° = 137°26'40″ = 0.74327343317 rad
∠ B' = β' = 120.2122277096° = 120°12'44″ = 1.0433492617 rad
∠ C' = γ' = 102.3433265413° = 102°20'36″ = 1.35553657049 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.