# 8 17 18 triangle

### Acute scalene triangle.

Sides: a = 8   b = 17   c = 18

Area: T = 67.61224064059
Perimeter: p = 43
Semiperimeter: s = 21.5

Angle ∠ A = α = 26.22658839295° = 26°13'33″ = 0.45877280238 rad
Angle ∠ B = β = 69.89444902121° = 69°53'40″ = 1.22198889832 rad
Angle ∠ C = γ = 83.88796258585° = 83°52'47″ = 1.46439756466 rad

Height: ha = 16.90331016015
Height: hb = 7.95444007536
Height: hc = 7.51224896007

Median: ma = 17.04440605491
Median: mb = 11.03440382454
Median: mc = 9.77224101428

Inradius: r = 3.14547630886
Circumradius: R = 9.05215932287

Vertex coordinates: A[18; 0] B[0; 0] C[2.75; 7.51224896007]
Centroid: CG[6.91766666667; 2.50441632002]
Coordinates of the circumscribed circle: U[9; 0.96550595722]
Coordinates of the inscribed circle: I[4.5; 3.14547630886]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 153.7744116071° = 153°46'27″ = 0.45877280238 rad
∠ B' = β' = 110.1065509788° = 110°6'20″ = 1.22198889832 rad
∠ C' = γ' = 96.12203741415° = 96°7'13″ = 1.46439756466 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.