# 17 17 26 triangle

### Obtuse isosceles triangle.

Sides: a = 17   b = 17   c = 26

Area: T = 142.4087864951
Perimeter: p = 60
Semiperimeter: s = 30

Angle ∠ A = α = 40.11991668984° = 40°7'9″ = 0.77002115555 rad
Angle ∠ B = β = 40.11991668984° = 40°7'9″ = 0.77002115555 rad
Angle ∠ C = γ = 99.76216662032° = 99°45'42″ = 1.74111695425 rad

Height: ha = 16.75438664649
Height: hb = 16.75438664649
Height: hc = 10.95444511501

Median: ma = 20.25546291005
Median: mb = 20.25546291005
Median: mc = 10.95444511501

Inradius: r = 4.74769288317
Circumradius: R = 13.19109849266

Vertex coordinates: A[26; 0] B[0; 0] C[13; 10.95444511501]
Centroid: CG[13; 3.65114837167]
Coordinates of the circumscribed circle: U[13; -2.23765337765]
Coordinates of the inscribed circle: I[13; 4.74769288317]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 139.8810833102° = 139°52'51″ = 0.77002115555 rad
∠ B' = β' = 139.8810833102° = 139°52'51″ = 0.77002115555 rad
∠ C' = γ' = 80.23883337968° = 80°14'18″ = 1.74111695425 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.