# 18 27 28 triangle

### Acute scalene triangle.

Sides: a = 18   b = 27   c = 28

Area: T = 233.5098966637
Perimeter: p = 73
Semiperimeter: s = 36.5

Angle ∠ A = α = 38.15219102718° = 38°9'7″ = 0.66658764502 rad
Angle ∠ B = β = 67.91443583076° = 67°54'52″ = 1.18553291618 rad
Angle ∠ C = γ = 73.93437314206° = 73°56'1″ = 1.29903870416 rad

Height: ha = 25.94554407375
Height: hb = 17.29769604916
Height: hc = 16.67992119027

Median: ma = 25.99903828367
Median: mb = 19.28108194847
Median: mc = 18.18796589627

Inradius: r = 6.39875059353
Circumradius: R = 14.56990336821

Vertex coordinates: A[28; 0] B[0; 0] C[6.76878571429; 16.67992119027]
Centroid: CG[11.58992857143; 5.56597373009]
Coordinates of the circumscribed circle: U[14; 4.03219650828]
Coordinates of the inscribed circle: I[9.5; 6.39875059353]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.8488089728° = 141°50'53″ = 0.66658764502 rad
∠ B' = β' = 112.0865641692° = 112°5'8″ = 1.18553291618 rad
∠ C' = γ' = 106.0666268579° = 106°3'59″ = 1.29903870416 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.