# Triangle calculator

You have entered side a, b and c.

### Equilateral triangle.

Sides: a = 70   b = 70   c = 70

Area: T = 2121.762223927
Perimeter: p = 210
Semiperimeter: s = 105

Angle ∠ A = α = 60° = 1.04771975512 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 60° = 1.04771975512 rad

Height: ha = 60.62217782649
Height: hb = 60.62217782649
Height: hc = 60.62217782649

Median: ma = 60.62217782649
Median: mb = 60.62217782649
Median: mc = 60.62217782649

Vertex coordinates: A[70; 0] B[0; 0] C[35; 60.62217782649]
Centroid: CG[35; 20.20772594216]
Coordinates of the circumscribed circle: U[35; 20.20772594216]
Coordinates of the inscribed circle: I[35; 20.20772594216]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 120° = 1.04771975512 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 120° = 1.04771975512 rad

# How did we calculate this triangle?

### 1. Input data entered: side a, b and c. 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. ### 2. The triangle circumference is the sum of the lengths of its three sides ### 3. Semiperimeter of the triangle ### 4. The triangle area using Heron's formula ### 5. Calculate the heights of the triangle from its area. ### 6. Calculation of the inner angles of the triangle using a Law of Cosines    