Equilateral triangle calculator (a)
Equilateral triangle.
Sides: a = 9 b = 9 c = 9Area: T = 35.07440288533
Perimeter: p = 27
Semiperimeter: s = 13.5
Angle ∠ A = α = 60° = 1.04771975512 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 60° = 1.04771975512 rad
Height: ha = 7.79442286341
Height: hb = 7.79442286341
Height: hc = 7.79442286341
Median: ma = 7.79442286341
Median: mb = 7.79442286341
Median: mc = 7.79442286341
Inradius: r = 2.59880762114
Circumradius: R = 5.19661524227
Vertex coordinates: A[9; 0] B[0; 0] C[4.5; 7.79442286341]
Centroid: CG[4.5; 2.59880762114]
Coordinates of the circumscribed circle: U[4.5; 2.59880762114]
Coordinates of the inscribed circle: I[4.5; 2.59880762114]
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
Calculate another triangle
How did we calculate this triangle?
1. Input data entered: side a

2. 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.

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

8. Inradius

9. Circumradius
