# Equilateral triangle calculator (h)

Please enter one property of the equilateral triangle

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

You have entered height h.

### Equilateral triangle.

Sides: a = 3.46441016151   b = 3.46441016151   c = 3.46441016151

Area: T = 5.19661524227
Perimeter: p = 10.39223048454
Semiperimeter: s = 5.19661524227

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

Height: ha = 3
Height: hb = 3
Height: hc = 3

Median: ma = 3
Median: mb = 3
Median: mc = 3

Inradius: r = 1
Circumradius: R = 2

Vertex coordinates: A[3.46441016151; 0] B[0; 0] C[1.73220508076; 3]
Centroid: CG[1.73220508076; 1]
Coordinates of the circumscribed circle: U[1.73220508076; 1]
Coordinates of the inscribed circle: I[1.73220508076; 1]

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: height h ### 2. From height h we calculate side a - Pythagorean theorem: ### 3. From side a 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. ### 4. The triangle circumference is the sum of the lengths of its three sides ### 5. Semiperimeter of the triangle ### 6. The triangle area using Heron's formula ### 7. Calculate the heights of the triangle from its area. ### 8. Calculation of the inner angles of the triangle using a Law of Cosines    