# 8 14 18 triangle

### Obtuse scalene triangle.

Sides: a = 8   b = 14   c = 18

Area: T = 53.666563146
Perimeter: p = 40
Semiperimeter: s = 20

Angle ∠ A = α = 25.20987652968° = 25°12'32″ = 0.44399759548 rad
Angle ∠ B = β = 48.19896851042° = 48°11'23″ = 0.84110686706 rad
Angle ∠ C = γ = 106.6021549599° = 106°36'6″ = 1.86105480282 rad

Height: ha = 13.4166407865
Height: hb = 7.667651878
Height: hc = 5.963284794

Median: ma = 15.62204993518
Median: mb = 12.04215945788
Median: mc = 7

Vertex coordinates: A[18; 0] B[0; 0] C[5.33333333333; 5.963284794]
Centroid: CG[7.77877777778; 1.988761598]
Coordinates of the circumscribed circle: U[9; -2.6833281573]
Coordinates of the inscribed circle: I[6; 2.6833281573]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 154.7911234703° = 154°47'28″ = 0.44399759548 rad
∠ B' = β' = 131.8110314896° = 131°48'37″ = 0.84110686706 rad
∠ C' = γ' = 73.3988450401° = 73°23'54″ = 1.86105480282 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    