# 18 21 29 triangle

### Obtuse scalene triangle.

Sides: a = 18   b = 21   c = 29

Area: T = 188.0432548377
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 38.13771011066° = 38°8'14″ = 0.66656179815 rad
Angle ∠ B = β = 46.09332596507° = 46°5'36″ = 0.80444791439 rad
Angle ∠ C = γ = 95.77696392427° = 95°46'11″ = 1.67114955282 rad

Height: ha = 20.89436164863
Height: hb = 17.90988141311
Height: hc = 12.96884516122

Median: ma = 23.66443191324
Median: mb = 21.73113138121
Median: mc = 13.12444047484

Inradius: r = 5.53106631875
Circumradius: R = 14.57438292937

Vertex coordinates: A[29; 0] B[0; 0] C[12.48327586207; 12.96884516122]
Centroid: CG[13.82875862069; 4.32328172041]
Coordinates of the circumscribed circle: U[14.5; -1.46550939502]
Coordinates of the inscribed circle: I[13; 5.53106631875]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 141.8632898893° = 141°51'46″ = 0.66656179815 rad
∠ B' = β' = 133.9076740349° = 133°54'24″ = 0.80444791439 rad
∠ C' = γ' = 84.23303607573° = 84°13'49″ = 1.67114955282 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.