# 3.1 4.5 5.2 triangle

### Acute scalene triangle.

Sides: a = 3.1   b = 4.5   c = 5.2

Area: T = 6.93992795015
Perimeter: p = 12.8
Semiperimeter: s = 6.4

Angle ∠ A = α = 36.37773613942° = 36°22'38″ = 0.63549047295 rad
Angle ∠ B = β = 59.42437311947° = 59°25'25″ = 1.03771397632 rad
Angle ∠ C = γ = 84.19989074111° = 84°11'56″ = 1.47695481609 rad

Height: ha = 4.47769545171
Height: hb = 3.08441242229
Height: hc = 2.66989536544

Median: ma = 4.60989586676
Median: mb = 3.64217715469
Median: mc = 2.85883211856

Inradius: r = 1.08442624221
Circumradius: R = 2.61333837088

Vertex coordinates: A[5.2; 0] B[0; 0] C[1.57769230769; 2.66989536544]
Centroid: CG[2.2598974359; 0.89896512181]
Coordinates of the circumscribed circle: U[2.6; 0.26441484609]
Coordinates of the inscribed circle: I[1.9; 1.08442624221]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.6232638606° = 143°37'22″ = 0.63549047295 rad
∠ B' = β' = 120.5766268805° = 120°34'35″ = 1.03771397632 rad
∠ C' = γ' = 95.80110925889° = 95°48'4″ = 1.47695481609 rad

# How did we calculate this triangle?

### 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    