# 28 28 30 triangle

### Acute isosceles triangle.

Sides: a = 28   b = 28   c = 30

Area: T = 354.6487712526
Perimeter: p = 86
Semiperimeter: s = 43

Angle ∠ A = α = 57.60876345142° = 57°36'27″ = 1.00554428966 rad
Angle ∠ B = β = 57.60876345142° = 57°36'27″ = 1.00554428966 rad
Angle ∠ C = γ = 64.78547309717° = 64°47'5″ = 1.13107068605 rad

Height: ha = 25.33219794662
Height: hb = 25.33219794662
Height: hc = 23.64331808351

Median: ma = 25.41765300543
Median: mb = 25.41765300543
Median: mc = 23.64331808351

Inradius: r = 8.24876212215
Circumradius: R = 16.587983343

Vertex coordinates: A[30; 0] B[0; 0] C[15; 23.64331808351]
Centroid: CG[15; 7.88110602784]
Coordinates of the circumscribed circle: U[15; 7.06333474051]
Coordinates of the inscribed circle: I[15; 8.24876212215]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 122.3922365486° = 122°23'33″ = 1.00554428966 rad
∠ B' = β' = 122.3922365486° = 122°23'33″ = 1.00554428966 rad
∠ C' = γ' = 115.2155269028° = 115°12'55″ = 1.13107068605 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.