# 18 28 29 triangle

### Acute scalene triangle.

Sides: a = 18   b = 28   c = 29

Area: T = 242.999884259
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 36.76439249588° = 36°45'50″ = 0.64216515365 rad
Angle ∠ B = β = 68.59659541323° = 68°35'45″ = 1.19772252532 rad
Angle ∠ C = γ = 74.64401209089° = 74°38'24″ = 1.30327158639 rad

Height: ha = 276.9998713989
Height: hb = 17.3577060185
Height: hc = 16.75985408683

Median: ma = 27.04662566726
Median: mb = 19.66596032513
Median: mc = 18.54404962177

Inradius: r = 6.48799691357
Circumradius: R = 15.03771086589

Vertex coordinates: A[29; 0] B[0; 0] C[6.56989655172; 16.75985408683]
Centroid: CG[11.85663218391; 5.58661802894]
Coordinates of the circumscribed circle: U[14.5; 3.98330436626]
Coordinates of the inscribed circle: I[9.5; 6.48799691357]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 143.2366075041° = 143°14'10″ = 0.64216515365 rad
∠ B' = β' = 111.4044045868° = 111°24'15″ = 1.19772252532 rad
∠ C' = γ' = 105.3659879091° = 105°21'36″ = 1.30327158639 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.