# 11 20 25 triangle

### Obtuse scalene triangle.

Sides: a = 11   b = 20   c = 25

Area: T = 106.8833113727
Perimeter: p = 56
Semiperimeter: s = 28

Angle ∠ A = α = 25.31110651555° = 25°18'40″ = 0.44217614242 rad
Angle ∠ B = β = 51.01769167401° = 51°1'1″ = 0.89904131713 rad
Angle ∠ C = γ = 103.6722018104° = 103°40'19″ = 1.80994180581 rad

Height: ha = 19.43332934049
Height: hb = 10.68883113727
Height: hc = 8.55106490982

Median: ma = 21.9660191256
Median: mb = 16.52327116419
Median: mc = 10.21102889283

Inradius: r = 3.81772540617
Circumradius: R = 12.86545204285

Vertex coordinates: A[25; 0] B[0; 0] C[6.92; 8.55106490982]
Centroid: CG[10.64; 2.85502163661]
Coordinates of the circumscribed circle: U[12.5; -3.04107048285]
Coordinates of the inscribed circle: I[8; 3.81772540617]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.6898934845° = 154°41'20″ = 0.44217614242 rad
∠ B' = β' = 128.983308326° = 128°58'59″ = 0.89904131713 rad
∠ C' = γ' = 76.32879818956° = 76°19'41″ = 1.80994180581 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.