# 9 14 21 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 14   c = 21

Area: T = 47.83330429724
Perimeter: p = 44
Semiperimeter: s = 22

Angle ∠ A = α = 18.98994985755° = 18°59'22″ = 0.33114292734 rad
Angle ∠ B = β = 30.40990349246° = 30°24'33″ = 0.53107377818 rad
Angle ∠ C = γ = 130.60114665° = 130°36'5″ = 2.27994255984 rad

Height: ha = 10.6329565105
Height: hb = 6.83332918532
Height: hc = 4.55655279021

Median: ma = 17.27699160392
Median: mb = 14.56602197786
Median: mc = 5.31550729064

Inradius: r = 2.1744229226
Circumradius: R = 13.82993522405

Vertex coordinates: A[21; 0] B[0; 0] C[7.76219047619; 4.55655279021]
Centroid: CG[9.58773015873; 1.51985093007]
Coordinates of the circumscribed circle: U[10.5; -99.0000546327]
Coordinates of the inscribed circle: I[8; 2.1744229226]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.0110501425° = 161°38″ = 0.33114292734 rad
∠ B' = β' = 149.5910965075° = 149°35'27″ = 0.53107377818 rad
∠ C' = γ' = 49.39985335° = 49°23'55″ = 2.27994255984 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 ### 6. Inradius ### 7. Circumradius ### 8. Calculation of medians #### Look also our friend's collection of math examples and problems:

See more informations about triangles or more information about solving triangles.