# 4 26 26 triangle

### Acute isosceles triangle.

Sides: a = 4   b = 26   c = 26

Area: T = 51.84659255873
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 8.82334515715° = 8°49'24″ = 0.15439982813 rad
Angle ∠ B = β = 85.58882742142° = 85°35'18″ = 1.49437971861 rad
Angle ∠ C = γ = 85.58882742142° = 85°35'18″ = 1.49437971861 rad

Height: ha = 25.92329627936
Height: hb = 3.98881481221
Height: hc = 3.98881481221

Median: ma = 25.92329627936
Median: mb = 13.30441346957
Median: mc = 13.30441346957

Inradius: r = 1.85216401995
Circumradius: R = 13.03986330718

Vertex coordinates: A[26; 0] B[0; 0] C[0.30876923077; 3.98881481221]
Centroid: CG[8.76992307692; 1.32993827074]
Coordinates of the circumscribed circle: U[13; 1.00329717748]
Coordinates of the inscribed circle: I[2; 1.85216401995]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 171.1776548428° = 171°10'36″ = 0.15439982813 rad
∠ B' = β' = 94.41217257858° = 94°24'42″ = 1.49437971861 rad
∠ C' = γ' = 94.41217257858° = 94°24'42″ = 1.49437971861 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    