# 10 14 18 triangle

### Obtuse scalene triangle.

Sides: a = 10   b = 14   c = 18

Area: T = 69.64991205975
Perimeter: p = 42
Semiperimeter: s = 21

Angle ∠ A = α = 33.55773097619° = 33°33'26″ = 0.58656855435 rad
Angle ∠ B = β = 50.70435197608° = 50°42'13″ = 0.88549433622 rad
Angle ∠ C = γ = 95.73991704773° = 95°44'21″ = 1.6710963748 rad

Height: ha = 13.93298241195
Height: hb = 9.95498743711
Height: hc = 7.73987911775

Median: ma = 15.33297097168
Median: mb = 12.76771453348
Median: mc = 8.18553527719

Inradius: r = 3.31766247904
Circumradius: R = 9.04553403373

Vertex coordinates: A[18; 0] B[0; 0] C[6.33333333333; 7.73987911775]
Centroid: CG[8.11111111111; 2.58795970592]
Coordinates of the circumscribed circle: U[9; -0.90545340337]
Coordinates of the inscribed circle: I[7; 3.31766247904]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.4432690238° = 146°26'34″ = 0.58656855435 rad
∠ B' = β' = 129.2966480239° = 129°17'47″ = 0.88549433622 rad
∠ C' = γ' = 84.26108295227° = 84°15'39″ = 1.6710963748 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    