# 11 11 16 triangle

### Obtuse isosceles triangle.

Sides: a = 11   b = 11   c = 16

Area: T = 60.39986754822
Perimeter: p = 38
Semiperimeter: s = 19

Angle ∠ A = α = 43.34217582272° = 43°20'30″ = 0.75664563847 rad
Angle ∠ B = β = 43.34217582272° = 43°20'30″ = 0.75664563847 rad
Angle ∠ C = γ = 93.31664835456° = 93°18'59″ = 1.62986798843 rad

Height: ha = 10.98215773604
Height: hb = 10.98215773604
Height: hc = 7.55498344353

Median: ma = 12.58797456254
Median: mb = 12.58797456254
Median: mc = 7.55498344353

Inradius: r = 3.1798877657
Circumradius: R = 8.01334207602

Vertex coordinates: A[16; 0] B[0; 0] C[8; 7.55498344353]
Centroid: CG[8; 2.51766114784]
Coordinates of the circumscribed circle: U[8; -0.4643586325]
Coordinates of the inscribed circle: I[8; 3.1798877657]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 136.6588241773° = 136°39'30″ = 0.75664563847 rad
∠ B' = β' = 136.6588241773° = 136°39'30″ = 0.75664563847 rad
∠ C' = γ' = 86.68435164544° = 86°41'1″ = 1.62986798843 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    