# 13 25 25 triangle

### Acute isosceles triangle.

Sides: a = 13   b = 25   c = 25

Area: T = 156.911140016
Perimeter: p = 63
Semiperimeter: s = 31.5

Angle ∠ A = α = 30.14401242898° = 30°8'24″ = 0.52660444058 rad
Angle ∠ B = β = 74.93299378551° = 74°55'48″ = 1.30877741239 rad
Angle ∠ C = γ = 74.93299378551° = 74°55'48″ = 1.30877741239 rad

Height: ha = 24.14402154091
Height: hb = 12.55329120128
Height: hc = 12.55329120128

Median: ma = 24.14402154091
Median: mb = 15.51661206492
Median: mc = 15.51661206492

Inradius: r = 4.98113142908
Circumradius: R = 12.94552034584

Vertex coordinates: A[25; 0] B[0; 0] C[3.38; 12.55329120128]
Centroid: CG[9.46; 4.18443040043]
Coordinates of the circumscribed circle: U[12.5; 3.36657528992]
Coordinates of the inscribed circle: I[6.5; 4.98113142908]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 149.865987571° = 149°51'36″ = 0.52660444058 rad
∠ B' = β' = 105.0770062145° = 105°4'12″ = 1.30877741239 rad
∠ C' = γ' = 105.0770062145° = 105°4'12″ = 1.30877741239 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.