# 6 25 25 triangle

### Acute isosceles triangle.

Sides: a = 6   b = 25   c = 25

Area: T = 74.45880418759
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 13.78442051587° = 13°47'3″ = 0.24105797648 rad
Angle ∠ B = β = 83.10878974207° = 83°6'28″ = 1.45105064444 rad
Angle ∠ C = γ = 83.10878974207° = 83°6'28″ = 1.45105064444 rad

Height: ha = 24.8199347292
Height: hb = 5.95766433501
Height: hc = 5.95766433501

Median: ma = 24.8199347292
Median: mb = 13.22003787824
Median: mc = 13.22003787824

Inradius: r = 2.65992157813
Circumradius: R = 12.59109838129

Vertex coordinates: A[25; 0] B[0; 0] C[0.72; 5.95766433501]
Centroid: CG[8.57333333333; 1.98655477834]
Coordinates of the circumscribed circle: U[12.5; 1.51109180575]
Coordinates of the inscribed circle: I[3; 2.65992157813]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 166.2165794841° = 166°12'57″ = 0.24105797648 rad
∠ B' = β' = 96.89221025793° = 96°53'32″ = 1.45105064444 rad
∠ C' = γ' = 96.89221025793° = 96°53'32″ = 1.45105064444 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    