# 9 12 16 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 12   c = 16

Area: T = 53.44109721094
Perimeter: p = 37
Semiperimeter: s = 18.5

Angle ∠ A = α = 33.82662859376° = 33°49'35″ = 0.59903800633 rad
Angle ∠ B = β = 47.92222147824° = 47°55'20″ = 0.83664004328 rad
Angle ∠ C = γ = 98.251149928° = 98°15'5″ = 1.71548121575 rad

Height: ha = 11.87657715799
Height: hb = 8.90768286849
Height: hc = 6.68801215137

Median: ma = 13.40770876778
Median: mb = 11.51108644332
Median: mc = 6.96441941386

Inradius: r = 2.88987011951
Circumradius: R = 8.08436852877

Vertex coordinates: A[16; 0] B[0; 0] C[6.031125; 6.68801215137]
Centroid: CG[7.344375; 2.22767071712]
Coordinates of the circumscribed circle: U[8; -1.16601585367]
Coordinates of the inscribed circle: I[6.5; 2.88987011951]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 146.1743714062° = 146°10'25″ = 0.59903800633 rad
∠ B' = β' = 132.0787785218° = 132°4'40″ = 0.83664004328 rad
∠ C' = γ' = 81.749850072° = 81°44'55″ = 1.71548121575 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.