# 25 25 27 triangle

### Acute isosceles triangle.

Sides: a = 25   b = 25   c = 27

Area: T = 284.0621943069
Perimeter: p = 77
Semiperimeter: s = 38.5

Angle ∠ A = α = 57.31663611537° = 57°18'59″ = 11.0003592174 rad
Angle ∠ B = β = 57.31663611537° = 57°18'59″ = 11.0003592174 rad
Angle ∠ C = γ = 65.36772776925° = 65°22'2″ = 1.14108742188 rad

Height: ha = 22.72549554455
Height: hb = 22.72549554455
Height: hc = 21.04216254125

Median: ma = 22.82199474145
Median: mb = 22.82199474145
Median: mc = 21.04216254125

Inradius: r = 7.37882322875
Circumradius: R = 14.85215142663

Vertex coordinates: A[27; 0] B[0; 0] C[13.5; 21.04216254125]
Centroid: CG[13.5; 7.01438751375]
Coordinates of the circumscribed circle: U[13.5; 6.19901111462]
Coordinates of the inscribed circle: I[13.5; 7.37882322875]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 122.6843638846° = 122°41'1″ = 11.0003592174 rad
∠ B' = β' = 122.6843638846° = 122°41'1″ = 11.0003592174 rad
∠ C' = γ' = 114.6332722307° = 114°37'58″ = 1.14108742188 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    