# 12 25 28 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 25   c = 28

Area: T = 149.9533117674
Perimeter: p = 65
Semiperimeter: s = 32.5

Angle ∠ A = α = 25.36884394418° = 25°22'6″ = 0.44327627944 rad
Angle ∠ B = β = 63.19990168207° = 63°11'56″ = 1.10330309275 rad
Angle ∠ C = γ = 91.43325437376° = 91°25'57″ = 1.59657989317 rad

Height: ha = 24.99221862789
Height: hb = 11.99662494139
Height: hc = 10.71109369767

Median: ma = 25.85553669477
Median: mb = 17.54328047928
Median: mc = 13.73295302177

Inradius: r = 4.61439420823
Circumradius: R = 14.00443770519

Vertex coordinates: A[28; 0] B[0; 0] C[5.41107142857; 10.71109369767]
Centroid: CG[11.13769047619; 3.57703123256]
Coordinates of the circumscribed circle: U[14; -0.35501094263]
Coordinates of the inscribed circle: I[7.5; 4.61439420823]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.6321560558° = 154°37'54″ = 0.44327627944 rad
∠ B' = β' = 116.8010983179° = 116°48'4″ = 1.10330309275 rad
∠ C' = γ' = 88.56774562624° = 88°34'3″ = 1.59657989317 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.