# 9 10 18 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 10   c = 18

Area: T = 27.33301573358
Perimeter: p = 37
Semiperimeter: s = 18.5

Angle ∠ A = α = 17.6788070483° = 17°40'41″ = 0.30985405353 rad
Angle ∠ B = β = 19.71991160383° = 19°43'9″ = 0.34441635005 rad
Angle ∠ C = γ = 142.6032813479° = 142°36'10″ = 2.48988886178 rad

Height: ha = 6.07333682968
Height: hb = 5.46660314672
Height: hc = 3.03766841484

Median: ma = 13.84773824241
Median: mb = 13.32329125945
Median: mc = 3.08222070015

Inradius: r = 1.47773058019
Circumradius: R = 14.81987950411

Vertex coordinates: A[18; 0] B[0; 0] C[8.47222222222; 3.03766841484]
Centroid: CG[8.82440740741; 1.01222280495]
Coordinates of the circumscribed circle: U[9; -11.77327093938]
Coordinates of the inscribed circle: I[8.5; 1.47773058019]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 162.3221929517° = 162°19'19″ = 0.30985405353 rad
∠ B' = β' = 160.2810883962° = 160°16'51″ = 0.34441635005 rad
∠ C' = γ' = 37.39771865213° = 37°23'50″ = 2.48988886178 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.