# 13 25 28 triangle

### Acute scalene triangle.

Sides: a = 13   b = 25   c = 28

Area: T = 162.4810768093
Perimeter: p = 66
Semiperimeter: s = 33

Angle ∠ A = α = 27.66604498993° = 27°39'38″ = 0.48327659233 rad
Angle ∠ B = β = 63.22110584075° = 63°13'16″ = 1.10334156258 rad
Angle ∠ C = γ = 89.11884916932° = 89°7'7″ = 1.55554111045 rad

Height: ha = 24.9977041245
Height: hb = 12.99884614474
Height: hc = 11.60657691495

Median: ma = 25.73442184649
Median: mb = 17.89655301682
Median: mc = 14.17774468788

Inradius: r = 4.92436596392
Circumradius: R = 14.00216570989

Vertex coordinates: A[28; 0] B[0; 0] C[5.85771428571; 11.60657691495]
Centroid: CG[11.28657142857; 3.86985897165]
Coordinates of the circumscribed circle: U[14; 0.21554101092]
Coordinates of the inscribed circle: I[8; 4.92436596392]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 152.3439550101° = 152°20'22″ = 0.48327659233 rad
∠ B' = β' = 116.7798941592° = 116°46'44″ = 1.10334156258 rad
∠ C' = γ' = 90.88215083068° = 90°52'53″ = 1.55554111045 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.