# 13 27 28 triangle

### Acute scalene triangle.

Sides: a = 13   b = 27   c = 28

Area: T = 173.1770436276
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 27.26660444507° = 27°15'58″ = 0.47658822497 rad
Angle ∠ B = β = 72.08797868606° = 72°4'47″ = 1.25880296049 rad
Angle ∠ C = γ = 80.65441686887° = 80°39'15″ = 1.40876807991 rad

Height: ha = 26.64216055809
Height: hb = 12.82774397241
Height: hc = 12.36993168769

Median: ma = 26.72554560298
Median: mb = 17.15437167984
Median: mc = 15.90659737206

Inradius: r = 5.09332481258
Circumradius: R = 14.18883340646

Vertex coordinates: A[28; 0] B[0; 0] C[4; 12.36993168769]
Centroid: CG[10.66766666667; 4.12331056256]
Coordinates of the circumscribed circle: U[14; 2.30440884378]
Coordinates of the inscribed circle: I[7; 5.09332481258]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.7343955549° = 152°44'2″ = 0.47658822497 rad
∠ B' = β' = 107.9220213139° = 107°55'13″ = 1.25880296049 rad
∠ C' = γ' = 99.34658313113° = 99°20'45″ = 1.40876807991 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.