# 4.2 6.4 7.6 triangle

### Acute scalene triangle.

Sides: a = 4.2   b = 6.4   c = 7.6

Area: T = 13.43883592749
Perimeter: p = 18.2
Semiperimeter: s = 9.1

Angle ∠ A = α = 33.54331004217° = 33°32'35″ = 0.58554375437 rad
Angle ∠ B = β = 57.35221825649° = 57°21'8″ = 1.0010984419 rad
Angle ∠ C = γ = 89.10547170134° = 89°6'17″ = 1.55551706909 rad

Height: ha = 6.39992187023
Height: hb = 4.19994872734
Height: hc = 3.53664103355

Median: ma = 6.70444761167
Median: mb = 5.24402290026
Median: mc = 3.85548670535

Inradius: r = 1.47767427775
Circumradius: R = 3.88004639521

Vertex coordinates: A[7.6; 0] B[0; 0] C[2.26657894737; 3.53664103355]
Centroid: CG[3.28985964912; 1.17988034452]
Coordinates of the circumscribed circle: U[3.8; 0.05993822493]
Coordinates of the inscribed circle: I[2.7; 1.47767427775]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.4576899578° = 146°27'25″ = 0.58554375437 rad
∠ B' = β' = 122.6487817435° = 122°38'52″ = 1.0010984419 rad
∠ C' = γ' = 90.89552829866° = 90°53'43″ = 1.55551706909 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    