# 9 18 25 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 18   c = 25

Area: T = 59.46442749893
Perimeter: p = 52
Semiperimeter: s = 26

Angle ∠ A = α = 15.32545113215° = 15°19'28″ = 0.26774631788 rad
Angle ∠ B = β = 31.90989763008° = 31°54'32″ = 0.55769166974 rad
Angle ∠ C = γ = 132.7676512378° = 132°45'59″ = 2.31772127774 rad

Height: ha = 13.21442833309
Height: hb = 6.60771416655
Height: hc = 4.75771419991

Median: ma = 21.31331414859
Median: mb = 16.49224225025
Median: mc = 6.80107352544

Inradius: r = 2.28770874996
Circumradius: R = 17.0277030098

Vertex coordinates: A[25; 0] B[0; 0] C[7.64; 4.75771419991]
Centroid: CG[10.88; 1.58657139997]
Coordinates of the circumscribed circle: U[12.5; -11.56215636468]
Coordinates of the inscribed circle: I[8; 2.28770874996]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 164.6755488678° = 164°40'32″ = 0.26774631788 rad
∠ B' = β' = 148.0911023699° = 148°5'28″ = 0.55769166974 rad
∠ C' = γ' = 47.23334876223° = 47°14'1″ = 2.31772127774 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.