# 11 28 30 triangle

### Acute scalene triangle.

Sides: a = 11   b = 28   c = 30

Area: T = 153.9954926865
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 21.50994443897° = 21°30'34″ = 0.37554106249 rad
Angle ∠ B = β = 68.95656238625° = 68°57'20″ = 1.20435026742 rad
Angle ∠ C = γ = 89.53549317478° = 89°32'6″ = 1.56326793545 rad

Height: ha = 27.99990776117
Height: hb = 110.9996376332
Height: hc = 10.26663284576

Median: ma = 28.49112267198
Median: mb = 17.7344147851
Median: mc = 15.0833103129

Inradius: r = 4.46436210685
Circumradius: R = 155.0004941529

Vertex coordinates: A[30; 0] B[0; 0] C[3.95; 10.26663284576]
Centroid: CG[11.31766666667; 3.42221094859]
Coordinates of the circumscribed circle: U[15; 0.12217572577]
Coordinates of the inscribed circle: I[6.5; 4.46436210685]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 158.491055561° = 158°29'26″ = 0.37554106249 rad
∠ B' = β' = 111.0444376137° = 111°2'40″ = 1.20435026742 rad
∠ C' = γ' = 90.46550682522° = 90°27'54″ = 1.56326793545 rad

# How did we calculate this triangle?

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. ### 1. The triangle circumference is the sum of the lengths of its three sides ### 2. Semiperimeter of the triangle ### 3. The triangle area using Heron's formula ### 4. Calculate the heights of the triangle from its area. ### 5. Calculation of the inner angles of the triangle using a Law of Cosines    