# 21 24 30 triangle

### Acute scalene triangle.

Sides: a = 21   b = 24   c = 30

Area: T = 250.297669894
Perimeter: p = 75
Semiperimeter: s = 37.5

Angle ∠ A = α = 44.04986256741° = 44°2'55″ = 0.7698793549 rad
Angle ∠ B = β = 52.61768015821° = 52°37' = 0.91883364295 rad
Angle ∠ C = γ = 83.33545727438° = 83°20'4″ = 1.45444626751 rad

Height: ha = 23.83877808514
Height: hb = 20.8588058245
Height: hc = 16.6866446596

Median: ma = 25.05549396327
Median: mb = 22.94655878112
Median: mc = 16.83774582405

Inradius: r = 6.67545786384
Circumradius: R = 15.10220769192

Vertex coordinates: A[30; 0] B[0; 0] C[12.75; 16.6866446596]
Centroid: CG[14.25; 5.56221488653]
Coordinates of the circumscribed circle: U[15; 1.75329196424]
Coordinates of the inscribed circle: I[13.5; 6.67545786384]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 135.9511374326° = 135°57'5″ = 0.7698793549 rad
∠ B' = β' = 127.3833198418° = 127°23' = 0.91883364295 rad
∠ C' = γ' = 96.66554272562° = 96°39'56″ = 1.45444626751 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.