# 16 16 25 triangle

### Obtuse isosceles triangle.

Sides: a = 16   b = 16   c = 25

Area: T = 124.8443652221
Perimeter: p = 57
Semiperimeter: s = 28.5

Angle ∠ A = α = 38.62548328731° = 38°37'29″ = 0.67441305067 rad
Angle ∠ B = β = 38.62548328731° = 38°37'29″ = 0.67441305067 rad
Angle ∠ C = γ = 102.7550334254° = 102°45'1″ = 1.79333316403 rad

Height: ha = 15.60554565277
Height: hb = 15.60554565277
Height: hc = 9.98774921777

Median: ma = 19.40436079119
Median: mb = 19.40436079119
Median: mc = 9.98774921777

Inradius: r = 4.38804790253
Circumradius: R = 12.81660300626

Vertex coordinates: A[25; 0] B[0; 0] C[12.5; 9.98774921777]
Centroid: CG[12.5; 3.32991640592]
Coordinates of the circumscribed circle: U[12.5; -2.82985378849]
Coordinates of the inscribed circle: I[12.5; 4.38804790253]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.3755167127° = 141°22'31″ = 0.67441305067 rad
∠ B' = β' = 141.3755167127° = 141°22'31″ = 0.67441305067 rad
∠ C' = γ' = 77.25496657461° = 77°14'59″ = 1.79333316403 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    