# Triangle calculator

Please enter what you know about the triangle:
You have entered side a, b and c.

### Equilateral triangle.

Sides: a = 60   b = 60   c = 60

Area: T = 1558.846572681
Perimeter: p = 180
Semiperimeter: s = 90

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

Height: ha = 51.96215242271
Height: hb = 51.96215242271
Height: hc = 51.96215242271

Median: ma = 51.96215242271
Median: mb = 51.96215242271
Median: mc = 51.96215242271

Inradius: r = 17.32105080757
Circumradius: R = 34.64110161514

Vertex coordinates: A[60; 0] B[0; 0] C[30; 51.96215242271]
Centroid: CG[30; 17.32105080757]
Coordinates of the circumscribed circle: U[30; 17.32105080757]
Coordinates of the inscribed circle: I[30; 17.32105080757]

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   