# Equilateral triangle calculator - result

Please enter one property of the equilateral triangle

Use symbols: a, h, T, p, r, R

You have entered side a, b and c (as equilateral triangle).

### Equilateral triangle.

Sides: a = 23   b = 23   c = 23

Area: T = 229.0643719301
Perimeter: p = 69
Semiperimeter: s = 34.5

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

Height: ha = 19.9198584287
Height: hb = 19.9198584287
Height: hc = 19.9198584287

Median: ma = 19.9198584287
Median: mb = 19.9198584287
Median: mc = 19.9198584287

Inradius: r = 6.64395280957
Circumradius: R = 13.27990561914

Vertex coordinates: A[23; 0] B[0; 0] C[11.5; 19.9198584287]
Centroid: CG[11.5; 6.64395280957]
Coordinates of the circumscribed circle: U[11.5; 6.64395280957]
Coordinates of the inscribed circle: I[11.5; 6.64395280957]

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 c (as equilateral triangle) ### 2. From we calculate b,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. ### 3. The triangle circumference is the sum of the lengths of its three sides ### 4. Semiperimeter of the triangle ### 5. The triangle area using Heron's formula ### 6. Calculate the heights of the triangle from its area. ### 7. Calculation of the inner angles of the triangle using a Law of Cosines   