# 16 18 25 triangle

### Obtuse scalene triangle.

Sides: a = 16   b = 18   c = 25

Area: T = 143.5659874269
Perimeter: p = 59
Semiperimeter: s = 29.5

Angle ∠ A = α = 39.6466111147° = 39°38'46″ = 0.69219551751 rad
Angle ∠ B = β = 45.8733090067° = 45°52'23″ = 0.80106364597 rad
Angle ∠ C = γ = 94.4810798786° = 94°28'51″ = 1.64990010187 rad

Height: ha = 17.94549842836
Height: hb = 15.95110971409
Height: hc = 11.48547899415

Median: ma = 20.26107995894
Median: mb = 18.96604852259
Median: mc = 11.56550335062

Inradius: r = 4.86664364159
Circumradius: R = 12.53883224886

Vertex coordinates: A[25; 0] B[0; 0] C[11.14; 11.48547899415]
Centroid: CG[12.04766666667; 3.82882633138]
Coordinates of the circumscribed circle: U[12.5; -0.98795564444]
Coordinates of the inscribed circle: I[11.5; 4.86664364159]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.3543888853° = 140°21'14″ = 0.69219551751 rad
∠ B' = β' = 134.1276909933° = 134°7'37″ = 0.80106364597 rad
∠ C' = γ' = 85.5199201214° = 85°31'9″ = 1.64990010187 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.