# 13 28 30 triangle

### Acute scalene triangle.

Sides: a = 13   b = 28   c = 30

Area: T = 181.5177044654
Perimeter: p = 71
Semiperimeter: s = 35.5

Angle ∠ A = α = 25.60662067164° = 25°36'22″ = 0.44769126161 rad
Angle ∠ B = β = 68.56987454962° = 68°34'7″ = 1.19767503729 rad
Angle ∠ C = γ = 85.82550477874° = 85°49'30″ = 1.49879296646 rad

Height: ha = 27.92656991776
Height: hb = 12.96655031896
Height: hc = 12.10111363103

Median: ma = 28.28798514848
Median: mb = 18.3988369493
Median: mc = 15.85987515272

Inradius: r = 5.11331561874
Circumradius: R = 15.0439909917

Vertex coordinates: A[30; 0] B[0; 0] C[4.75; 12.10111363103]
Centroid: CG[11.58333333333; 4.03437121034]
Coordinates of the circumscribed circle: U[15; 1.09549384967]
Coordinates of the inscribed circle: I[7.5; 5.11331561874]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.3943793284° = 154°23'38″ = 0.44769126161 rad
∠ B' = β' = 111.4311254504° = 111°25'53″ = 1.19767503729 rad
∠ C' = γ' = 94.17549522126° = 94°10'30″ = 1.49879296646 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.