# 6 16 18 triangle

### Obtuse scalene triangle.

Sides: a = 6   b = 16   c = 18

Area: T = 47.32986382648
Perimeter: p = 40
Semiperimeter: s = 20

Angle ∠ A = α = 19.18881364537° = 19°11'17″ = 0.33548961584 rad
Angle ∠ B = β = 61.21877953194° = 61°13'4″ = 1.06884520891 rad
Angle ∠ C = γ = 99.59440682269° = 99°35'39″ = 1.7388244406 rad

Height: ha = 15.77662127549
Height: hb = 5.91660797831
Height: hc = 5.2598737585

Median: ma = 16.76330546142
Median: mb = 10.77703296143
Median: mc = 8.06222577483

Inradius: r = 2.36664319132
Circumradius: R = 9.12876659511

Vertex coordinates: A[18; 0] B[0; 0] C[2.88988888889; 5.2598737585]
Centroid: CG[6.9632962963; 1.75329125283]
Coordinates of the circumscribed circle: U[9; -1.52112776585]
Coordinates of the inscribed circle: I[4; 2.36664319132]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 160.8121863546° = 160°48'43″ = 0.33548961584 rad
∠ B' = β' = 118.7822204681° = 118°46'56″ = 1.06884520891 rad
∠ C' = γ' = 80.40659317731° = 80°24'21″ = 1.7388244406 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.