# 10 20 25 triangle

### Obtuse scalene triangle.

Sides: a = 10   b = 20   c = 25

Area: T = 94.99217759598
Perimeter: p = 55
Semiperimeter: s = 27.5

Angle ∠ A = α = 22.33216450092° = 22°19'54″ = 0.39897607328 rad
Angle ∠ B = β = 49.45883981265° = 49°27'30″ = 0.86332118901 rad
Angle ∠ C = γ = 108.2109956864° = 108°12'36″ = 1.88986200307 rad

Height: ha = 18.9988355192
Height: hb = 9.4999177596
Height: hc = 7.59993420768

Median: ma = 22.07994021658
Median: mb = 16.2021851746
Median: mc = 9.68224583655

Inradius: r = 3.45442463985
Circumradius: R = 13.15990338992

Vertex coordinates: A[25; 0] B[0; 0] C[6.5; 7.59993420768]
Centroid: CG[10.5; 2.53331140256]
Coordinates of the circumscribed circle: U[12.5; -4.11221980935]
Coordinates of the inscribed circle: I[7.5; 3.45442463985]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 157.6688354991° = 157°40'6″ = 0.39897607328 rad
∠ B' = β' = 130.5421601874° = 130°32'30″ = 0.86332118901 rad
∠ C' = γ' = 71.79900431357° = 71°47'24″ = 1.88986200307 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.