# 1 25 25 triangle

### Acute isosceles triangle.

Sides: a = 1   b = 25   c = 25

Area: T = 12.497749975
Perimeter: p = 51
Semiperimeter: s = 25.5

Angle ∠ A = α = 2.29219839968° = 2°17'31″ = 0.04400026671 rad
Angle ∠ B = β = 88.85440080016° = 88°51'14″ = 1.55107949932 rad
Angle ∠ C = γ = 88.85440080016° = 88°51'14″ = 1.55107949932 rad

Height: ha = 24.99549994999
Height: hb = 10.99979998
Height: hc = 10.99979998

Median: ma = 24.99549994999
Median: mb = 12.52199840255
Median: mc = 12.52199840255

Inradius: r = 0.49900980294
Circumradius: R = 12.50325007502

Vertex coordinates: A[25; 0] B[0; 0] C[0.02; 10.99979998]
Centroid: CG[8.34; 0.333326666]
Coordinates of the circumscribed circle: U[12.5; 0.2550050015]
Coordinates of the inscribed circle: I[0.5; 0.49900980294]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 177.7088016003° = 177°42'29″ = 0.04400026671 rad
∠ B' = β' = 91.14659919984° = 91°8'46″ = 1.55107949932 rad
∠ C' = γ' = 91.14659919984° = 91°8'46″ = 1.55107949932 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    