5 8 8 triangle

Acute isosceles triangle.

Sides: a = 5   b = 8   c = 8

Area: T = 18.9988355192
Perimeter: p = 21
Semiperimeter: s = 10.5

Angle ∠ A = α = 36.42199137286° = 36°25'12″ = 0.63656474079 rad
Angle ∠ B = β = 71.79900431357° = 71°47'24″ = 1.25329726229 rad
Angle ∠ C = γ = 71.79900431357° = 71°47'24″ = 1.25329726229 rad

Height: ha = 7.59993420768
Height: hb = 4.7549588798
Height: hc = 4.7549588798

Median: ma = 7.59993420768
Median: mb = 5.3398539126
Median: mc = 5.3398539126

Vertex coordinates: A[8; 0] B[0; 0] C[1.56325; 4.7549588798]
Centroid: CG[3.18875; 1.5833196266]
Coordinates of the circumscribed circle: U[4; 1.31659033899]
Coordinates of the inscribed circle: I[2.5; 1.80993671611]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.5880086271° = 143°34'48″ = 0.63656474079 rad
∠ B' = β' = 108.2109956864° = 108°12'36″ = 1.25329726229 rad
∠ C' = γ' = 108.2109956864° = 108°12'36″ = 1.25329726229 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    