# 21 29 30 triangle

### Acute scalene triangle.

Sides: a = 21   b = 29   c = 30

Area: T = 289.1376645896
Perimeter: p = 80
Semiperimeter: s = 40

Angle ∠ A = α = 41.65879296759° = 41°39'29″ = 0.72770680324 rad
Angle ∠ B = β = 66.62201318843° = 66°37'12″ = 1.16327406495 rad
Angle ∠ C = γ = 71.72219384398° = 71°43'19″ = 1.25217839717 rad

Height: ha = 27.53768234187
Height: hb = 19.94404583377
Height: hc = 19.27657763931

Median: ma = 27.57326313579
Median: mb = 21.45334379529
Median: mc = 20.39660780544

Inradius: r = 7.22884161474
Circumradius: R = 15.79770290685

Vertex coordinates: A[30; 0] B[0; 0] C[8.33333333333; 19.27657763931]
Centroid: CG[12.77877777778; 6.42552587977]
Coordinates of the circumscribed circle: U[15; 4.95444048474]
Coordinates of the inscribed circle: I[11; 7.22884161474]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 138.3422070324° = 138°20'31″ = 0.72770680324 rad
∠ B' = β' = 113.3879868116° = 113°22'48″ = 1.16327406495 rad
∠ C' = γ' = 108.278806156° = 108°16'41″ = 1.25217839717 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.