# 15 26 28 triangle

### Acute scalene triangle.

Sides: a = 15   b = 26   c = 28

Area: T = 192.7943769349
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 31.98220267884° = 31°58'55″ = 0.55881916689 rad
Angle ∠ B = β = 66.64548997703° = 66°38'42″ = 1.16331729307 rad
Angle ∠ C = γ = 81.37330734413° = 81°22'23″ = 1.4220228054 rad

Height: ha = 25.70658359133
Height: hb = 14.833028995
Height: hc = 13.7710983525

Median: ma = 25.95766947048
Median: mb = 18.3176659084
Median: mc = 15.95330561335

Inradius: r = 5.58882251985
Circumradius: R = 14.16602086479

Vertex coordinates: A[28; 0] B[0; 0] C[5.94664285714; 13.7710983525]
Centroid: CG[11.31554761905; 4.59903278417]
Coordinates of the circumscribed circle: U[14; 2.12440312972]
Coordinates of the inscribed circle: I[8.5; 5.58882251985]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 148.0187973212° = 148°1'5″ = 0.55881916689 rad
∠ B' = β' = 113.355510023° = 113°21'18″ = 1.16331729307 rad
∠ C' = γ' = 98.62769265587° = 98°37'37″ = 1.4220228054 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.