# 12 16 18 triangle

### Acute scalene triangle.

Sides: a = 12   b = 16   c = 18

Area: T = 94.10110095589
Perimeter: p = 46
Semiperimeter: s = 23

Angle ∠ A = α = 40.80444376906° = 40°48'16″ = 0.71221717871 rad
Angle ∠ B = β = 60.61107200521° = 60°36'39″ = 1.05878566269 rad
Angle ∠ C = γ = 78.58548422573° = 78°35'5″ = 1.37215642395 rad

Height: ha = 15.68435015931
Height: hb = 11.76326261949
Height: hc = 10.45656677288

Median: ma = 15.93773774505
Median: mb = 13.03884048104
Median: mc = 10.90987121146

Inradius: r = 4.09113482417
Circumradius: R = 9.18216230671

Vertex coordinates: A[18; 0] B[0; 0] C[5.88988888889; 10.45656677288]
Centroid: CG[7.9632962963; 3.48552225763]
Coordinates of the circumscribed circle: U[9; 1.8177196232]
Coordinates of the inscribed circle: I[7; 4.09113482417]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 139.1965562309° = 139°11'44″ = 0.71221717871 rad
∠ B' = β' = 119.3899279948° = 119°23'21″ = 1.05878566269 rad
∠ C' = γ' = 101.4155157743° = 101°24'55″ = 1.37215642395 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.