# 12 16 25 triangle

### Obtuse scalene triangle.

Sides: a = 12   b = 16   c = 25

Area: T = 77.79441996552
Perimeter: p = 53
Semiperimeter: s = 26.5

Angle ∠ A = α = 22.89904870518° = 22°53'26″ = 0.43995143664 rad
Angle ∠ B = β = 31.24402652162° = 31°14'25″ = 0.54552454872 rad
Angle ∠ C = γ = 125.8699247732° = 125°52'9″ = 2.19768327999 rad

Height: ha = 12.96656999425
Height: hb = 9.72442749569
Height: hc = 6.22435359724

Median: ma = 20.11221853611
Median: mb = 17.903251379
Median: mc = 6.61443782777

Inradius: r = 2.93656301757
Circumradius: R = 15.4255314552

Vertex coordinates: A[25; 0] B[0; 0] C[10.26; 6.22435359724]
Centroid: CG[11.75333333333; 2.07545119908]
Coordinates of the circumscribed circle: U[12.5; -9.03882702453]
Coordinates of the inscribed circle: I[10.5; 2.93656301757]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 157.1109512948° = 157°6'34″ = 0.43995143664 rad
∠ B' = β' = 148.7659734784° = 148°45'35″ = 0.54552454872 rad
∠ C' = γ' = 54.1310752268° = 54°7'51″ = 2.19768327999 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.