# 12 17 25 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 17   c = 25

Area: T = 90
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 25.05876154183° = 25°3'27″ = 0.43773378917 rad
Angle ∠ B = β = 36.87698976458° = 36°52'12″ = 0.64435011088 rad
Angle ∠ C = γ = 118.0722486936° = 118°4'21″ = 2.0610753653 rad

Height: ha = 15
Height: hb = 10.58882352941
Height: hc = 7.2

Median: ma = 20.51882845287
Median: mb = 17.67105970471
Median: mc = 7.76220873481

Inradius: r = 3.33333333333
Circumradius: R = 14.16766666667

Vertex coordinates: A[25; 0] B[0; 0] C[9.6; 7.2]
Centroid: CG[11.53333333333; 2.4]
Coordinates of the circumscribed circle: U[12.5; -6.66766666667]
Coordinates of the inscribed circle: I[10; 3.33333333333]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.9422384582° = 154°56'33″ = 0.43773378917 rad
∠ B' = β' = 143.1330102354° = 143°7'48″ = 0.64435011088 rad
∠ C' = γ' = 61.92875130641° = 61°55'39″ = 2.0610753653 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.