# 20 27 28 triangle

### Acute scalene triangle.

Sides: a = 20   b = 27   c = 28

Area: T = 255.8533351551
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 42.59988128925° = 42°35'56″ = 0.74334895424 rad
Angle ∠ B = β = 66.03105176822° = 66°1'50″ = 1.15224499404 rad
Angle ∠ C = γ = 71.37106694253° = 71°22'14″ = 1.24656531708 rad

Height: ha = 25.58553351551
Height: hb = 18.95221001149
Height: hc = 18.27552393965

Median: ma = 25.62222559506
Median: mb = 20.242228248
Median: mc = 19.19663538205

Inradius: r = 6.82327560414
Circumradius: R = 14.774408827

Vertex coordinates: A[28; 0] B[0; 0] C[8.125; 18.27552393965]
Centroid: CG[12.04216666667; 6.09217464655]
Coordinates of the circumscribed circle: U[14; 4.72195004196]
Coordinates of the inscribed circle: I[10.5; 6.82327560414]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 137.4011187108° = 137°24'4″ = 0.74334895424 rad
∠ B' = β' = 113.9699482318° = 113°58'10″ = 1.15224499404 rad
∠ C' = γ' = 108.6299330575° = 108°37'46″ = 1.24656531708 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.