# 3 16 18 triangle

### Obtuse scalene triangle.

Sides: a = 3   b = 16   c = 18

Area: T = 18.93224456952
Perimeter: p = 37
Semiperimeter: s = 18.5

Angle ∠ A = α = 7.55548535785° = 7°33'17″ = 0.13218570695 rad
Angle ∠ B = β = 44.52334956372° = 44°31'25″ = 0.77770815934 rad
Angle ∠ C = γ = 127.9221650784° = 127°55'18″ = 2.23326539908 rad

Height: ha = 12.62216304634
Height: hb = 2.36765557119
Height: hc = 2.10436050772

Median: ma = 16.96331954537
Median: mb = 10.12442283657
Median: mc = 7.17663500472

Inradius: r = 1.0233375443
Circumradius: R = 11.40989855837

Vertex coordinates: A[18; 0] B[0; 0] C[2.13988888889; 2.10436050772]
Centroid: CG[6.7132962963; 0.70112016924]
Coordinates of the circumscribed circle: U[9; -7.012177239]
Coordinates of the inscribed circle: I[2.5; 1.0233375443]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 172.4455146422° = 172°26'43″ = 0.13218570695 rad
∠ B' = β' = 135.4776504363° = 135°28'35″ = 0.77770815934 rad
∠ C' = γ' = 52.07883492157° = 52°4'42″ = 2.23326539908 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.