# 20 28 29 triangle

### Acute scalene triangle.

Sides: a = 20   b = 28   c = 29

Area: T = 266.5466313987
Perimeter: p = 77
Semiperimeter: s = 38.5

Angle ∠ A = α = 41.03548543388° = 41°2'5″ = 0.71661933163 rad
Angle ∠ B = β = 66.7998528371° = 66°47'55″ = 1.16658542556 rad
Angle ∠ C = γ = 72.16766172902° = 72°10' = 1.26595450817 rad

Height: ha = 26.65546313987
Height: hb = 19.03990224276
Height: hc = 18.38325044129

Median: ma = 26.69326956301
Median: mb = 20.6033397778
Median: mc = 19.53884236826

Inradius: r = 6.92332808828
Circumradius: R = 15.23218744884

Vertex coordinates: A[29; 0] B[0; 0] C[7.87993103448; 18.38325044129]
Centroid: CG[12.29331034483; 6.1287501471]
Coordinates of the circumscribed circle: U[14.5; 4.66547615621]
Coordinates of the inscribed circle: I[10.5; 6.92332808828]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.9655145661° = 138°57'55″ = 0.71661933163 rad
∠ B' = β' = 113.2011471629° = 113°12'5″ = 1.16658542556 rad
∠ C' = γ' = 107.833338271° = 107°50' = 1.26595450817 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.