# 8 20 20 triangle

### Acute isosceles triangle.

Sides: a = 8   b = 20   c = 20

Area: T = 78.38436717691
Perimeter: p = 48
Semiperimeter: s = 24

Angle ∠ A = α = 23.07439180656° = 23°4'26″ = 0.40327158416 rad
Angle ∠ B = β = 78.46330409672° = 78°27'47″ = 1.3699438406 rad
Angle ∠ C = γ = 78.46330409672° = 78°27'47″ = 1.3699438406 rad

Height: ha = 19.59659179423
Height: hb = 7.83883671769
Height: hc = 7.83883671769

Median: ma = 19.59659179423
Median: mb = 11.48991252931
Median: mc = 11.48991252931

Inradius: r = 3.26659863237
Circumradius: R = 10.20662072616

Vertex coordinates: A[20; 0] B[0; 0] C[1.6; 7.83883671769]
Centroid: CG[7.2; 2.6132789059]
Coordinates of the circumscribed circle: U[10; 2.04112414523]
Coordinates of the inscribed circle: I[4; 3.26659863237]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.9266081934° = 156°55'34″ = 0.40327158416 rad
∠ B' = β' = 101.5376959033° = 101°32'13″ = 1.3699438406 rad
∠ C' = γ' = 101.5376959033° = 101°32'13″ = 1.3699438406 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.