# 25 26 26 triangle

### Acute isosceles triangle.

Sides: a = 25   b = 26   c = 26

Area: T = 284.975532788
Perimeter: p = 77
Semiperimeter: s = 38.5

Angle ∠ A = α = 57.47113074898° = 57°28'17″ = 1.00330635411 rad
Angle ∠ B = β = 61.26443462551° = 61°15'52″ = 1.06992645562 rad
Angle ∠ C = γ = 61.26443462551° = 61°15'52″ = 1.06992645562 rad

Height: ha = 22.79880262304
Height: hb = 21.92111790677
Height: hc = 21.92111790677

Median: ma = 22.79880262304
Median: mb = 21.94331082575
Median: mc = 21.94331082575

Inradius: r = 7.40219565683
Circumradius: R = 14.82658448598

Vertex coordinates: A[26; 0] B[0; 0] C[12.01992307692; 21.92111790677]
Centroid: CG[12.67330769231; 7.30770596892]
Coordinates of the circumscribed circle: U[13; 7.12878100287]
Coordinates of the inscribed circle: I[12.5; 7.40219565683]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 122.529869251° = 122°31'43″ = 1.00330635411 rad
∠ B' = β' = 118.7365653745° = 118°44'8″ = 1.06992645562 rad
∠ C' = γ' = 118.7365653745° = 118°44'8″ = 1.06992645562 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    