# 9 21 24 triangle

### Obtuse scalene triangle.

Sides: a = 9   b = 21   c = 24

Area: T = 93.53107436087
Perimeter: p = 54
Semiperimeter: s = 27

Angle ∠ A = α = 21.78767892983° = 21°47'12″ = 0.38802512067 rad
Angle ∠ B = β = 60° = 1.04771975512 rad
Angle ∠ C = γ = 98.21332107017° = 98°12'48″ = 1.71441438957 rad

Height: ha = 20.78546096908
Height: hb = 8.90876898675
Height: hc = 7.79442286341

Median: ma = 22.0966379794
Median: mb = 14.77332867027
Median: mc = 10.81766538264

Inradius: r = 3.46441016151
Circumradius: R = 12.1244355653

Vertex coordinates: A[24; 0] B[0; 0] C[4.5; 7.79442286341]
Centroid: CG[9.5; 2.59880762114]
Coordinates of the circumscribed circle: U[12; -1.73220508076]
Coordinates of the inscribed circle: I[6; 3.46441016151]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 158.2133210702° = 158°12'48″ = 0.38802512067 rad
∠ B' = β' = 120° = 1.04771975512 rad
∠ C' = γ' = 81.78767892983° = 81°47'12″ = 1.71441438957 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.