# 1 20 20 triangle

### Acute isosceles triangle.

Sides: a = 1   b = 20   c = 20

Area: T = 9.99768745116
Perimeter: p = 41
Semiperimeter: s = 20.5

Angle ∠ A = α = 2.86550874751° = 2°51'54″ = 0.05500052098 rad
Angle ∠ B = β = 88.56774562624° = 88°34'3″ = 1.54657937219 rad
Angle ∠ C = γ = 88.56774562624° = 88°34'3″ = 1.54657937219 rad

Height: ha = 19.99437490231
Height: hb = 10.9996874512
Height: hc = 10.9996874512

Median: ma = 19.99437490231
Median: mb = 10.02549688279
Median: mc = 10.02549688279

Inradius: r = 0.48876524152
Circumradius: R = 10.00331264656

Vertex coordinates: A[20; 0] B[0; 0] C[0.025; 10.9996874512]
Centroid: CG[6.675; 0.33332291504]
Coordinates of the circumscribed circle: U[10; 0.25500781616]
Coordinates of the inscribed circle: I[0.5; 0.48876524152]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 177.1354912525° = 177°8'6″ = 0.05500052098 rad
∠ B' = β' = 91.43325437376° = 91°25'57″ = 1.54657937219 rad
∠ C' = γ' = 91.43325437376° = 91°25'57″ = 1.54657937219 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.