# 10 28 28 triangle

### Acute isosceles triangle.

Sides: a = 10   b = 28   c = 28

Area: T = 137.754977314
Perimeter: p = 66
Semiperimeter: s = 33

Angle ∠ A = α = 20.57331212229° = 20°34'23″ = 0.35990687028 rad
Angle ∠ B = β = 79.71334393885° = 79°42'48″ = 1.39112619754 rad
Angle ∠ C = γ = 79.71334393885° = 79°42'48″ = 1.39112619754 rad

Height: ha = 27.55499546279
Height: hb = 9.839926951
Height: hc = 9.839926951

Median: ma = 27.55499546279
Median: mb = 15.68443871414
Median: mc = 15.68443871414

Inradius: r = 4.17442355497
Circumradius: R = 14.22986985694

Vertex coordinates: A[28; 0] B[0; 0] C[1.78657142857; 9.839926951]
Centroid: CG[9.92985714286; 3.28797565033]
Coordinates of the circumscribed circle: U[14; 2.54108390302]
Coordinates of the inscribed circle: I[5; 4.17442355497]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 159.4276878777° = 159°25'37″ = 0.35990687028 rad
∠ B' = β' = 100.2876560611° = 100°17'12″ = 1.39112619754 rad
∠ C' = γ' = 100.2876560611° = 100°17'12″ = 1.39112619754 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.