# 102 102 90 triangle

### Acute isosceles triangle.

Sides: a = 102   b = 102   c = 90

Area: T = 4119.165950165
Perimeter: p = 294
Semiperimeter: s = 147

Angle ∠ A = α = 63.8211031296° = 63°49'16″ = 1.11438871281 rad
Angle ∠ B = β = 63.8211031296° = 63°49'16″ = 1.11438871281 rad
Angle ∠ C = γ = 52.3587937408° = 52°21'29″ = 0.91438183973 rad

Height: ha = 80.76878333656
Height: hb = 80.76878333656
Height: hc = 91.53768778144

Median: ma = 81.55436633144
Median: mb = 81.55436633144
Median: mc = 91.53768778144

Inradius: r = 28.02114932085
Circumradius: R = 56.83295546474

Vertex coordinates: A[90; 0] B[0; 0] C[45; 91.53768778144]
Centroid: CG[45; 30.51222926048]
Coordinates of the circumscribed circle: U[45; 34.7077323167]
Coordinates of the inscribed circle: I[45; 28.02114932085]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 116.1798968704° = 116°10'44″ = 1.11438871281 rad
∠ B' = β' = 116.1798968704° = 116°10'44″ = 1.11438871281 rad
∠ C' = γ' = 127.6422062592° = 127°38'31″ = 0.91438183973 rad

# How did we calculate this triangle?

### 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    