# 17 18 26 triangle

### Obtuse scalene triangle.

Sides: a = 17   b = 18   c = 26

Area: T = 152.1877179158
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 40.57696972304° = 40°34'11″ = 0.70880747932 rad
Angle ∠ B = β = 43.52217409237° = 43°31'18″ = 0.76595976753 rad
Angle ∠ C = γ = 95.9098561846° = 95°54'31″ = 1.67439201851 rad

Height: ha = 17.90443740186
Height: hb = 16.91096865731
Height: hc = 11.70767060891

Median: ma = 20.68221178799
Median: mb = 20.03774649095
Median: mc = 11.72660393996

Inradius: r = 4.99897435789
Circumradius: R = 13.06994320705

Vertex coordinates: A[26; 0] B[0; 0] C[12.32769230769; 11.70767060891]
Centroid: CG[12.77656410256; 3.9022235363]
Coordinates of the circumscribed circle: U[13; -1.34553827131]
Coordinates of the inscribed circle: I[12.5; 4.99897435789]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 139.433030277° = 139°25'49″ = 0.70880747932 rad
∠ B' = β' = 136.4788259076° = 136°28'42″ = 0.76595976753 rad
∠ C' = γ' = 84.0911438154° = 84°5'29″ = 1.67439201851 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.