# 9 17 18 triangle

### Acute scalene triangle.

Sides: a = 9   b = 17   c = 18

Area: T = 75.63106816048
Perimeter: p = 44
Semiperimeter: s = 22

Angle ∠ A = α = 29.62548004283° = 29°37'29″ = 0.51770503077 rad
Angle ∠ B = β = 69.02110649855° = 69°1'16″ = 1.20546448372 rad
Angle ∠ C = γ = 81.35441345862° = 81°21'15″ = 1.42198975086 rad

Height: ha = 16.80768181344
Height: hb = 8.89877272476
Height: hc = 8.40334090672

Median: ma = 16.91989243157
Median: mb = 11.41327122105
Median: mc = 10.19880390272

Inradius: r = 3.43877582548
Circumradius: R = 9.10334483016

Vertex coordinates: A[18; 0] B[0; 0] C[3.22222222222; 8.40334090672]
Centroid: CG[7.07440740741; 2.80111363557]
Coordinates of the circumscribed circle: U[9; 1.36884922283]
Coordinates of the inscribed circle: I[5; 3.43877582548]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 150.3755199572° = 150°22'31″ = 0.51770503077 rad
∠ B' = β' = 110.9798935015° = 110°58'44″ = 1.20546448372 rad
∠ C' = γ' = 98.64658654138° = 98°38'45″ = 1.42198975086 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.