# 15 18 25 triangle

### Obtuse scalene triangle.

Sides: a = 15   b = 18   c = 25

Area: T = 133.6566275573
Perimeter: p = 58
Semiperimeter: s = 29

Angle ∠ A = α = 36.44333636683° = 36°26'36″ = 0.63660566865 rad
Angle ∠ B = β = 45.46659243544° = 45°27'57″ = 0.79435300774 rad
Angle ∠ C = γ = 98.09107119773° = 98°5'27″ = 1.71220058896 rad

Height: ha = 17.8210836743
Height: hb = 14.85106972859
Height: hc = 10.69325020458

Median: ma = 20.45111613362
Median: mb = 18.5477236991
Median: mc = 10.87442815855

Inradius: r = 4.60988370887
Circumradius: R = 12.62656697844

Vertex coordinates: A[25; 0] B[0; 0] C[10.52; 10.69325020458]
Centroid: CG[11.84; 3.56441673486]
Coordinates of the circumscribed circle: U[12.5; -1.77769461178]
Coordinates of the inscribed circle: I[11; 4.60988370887]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.5576636332° = 143°33'24″ = 0.63660566865 rad
∠ B' = β' = 134.5344075646° = 134°32'3″ = 0.79435300774 rad
∠ C' = γ' = 81.90992880227° = 81°54'33″ = 1.71220058896 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.