# 14 20 25 triangle

### Obtuse scalene triangle.

Sides: a = 14   b = 20   c = 25

Area: T = 139.812215076
Perimeter: p = 59
Semiperimeter: s = 29.5

Angle ∠ A = α = 34.0043849551° = 34°14″ = 0.5933479133 rad
Angle ∠ B = β = 53.02877198019° = 53°1'40″ = 0.92655083054 rad
Angle ∠ C = γ = 92.9688430647° = 92°58'6″ = 1.62326052152 rad

Height: ha = 19.97331643942
Height: hb = 13.9811215076
Height: hc = 11.18549720608

Median: ma = 21.52990501416
Median: mb = 17.62110101867
Median: mc = 11.90658808998

Inradius: r = 4.7399394941
Circumradius: R = 12.51767947885

Vertex coordinates: A[25; 0] B[0; 0] C[8.42; 11.18549720608]
Centroid: CG[11.14; 3.72883240203]
Coordinates of the circumscribed circle: U[12.5; -0.64881911587]
Coordinates of the inscribed circle: I[9.5; 4.7399394941]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.9966150449° = 145°59'46″ = 0.5933479133 rad
∠ B' = β' = 126.9722280198° = 126°58'20″ = 0.92655083054 rad
∠ C' = γ' = 87.0321569353° = 87°1'54″ = 1.62326052152 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    