# 21 24 24 triangle

### Acute isosceles triangle.

Sides: a = 21   b = 24   c = 24

Area: T = 226.6033039476
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 51.88989595447° = 51°53'20″ = 0.90656331895 rad
Angle ∠ B = β = 64.05655202276° = 64°3'20″ = 1.1187979732 rad
Angle ∠ C = γ = 64.05655202276° = 64°3'20″ = 1.1187979732 rad

Height: ha = 21.58112418549
Height: hb = 18.8843586623
Height: hc = 18.8843586623

Median: ma = 21.58112418549
Median: mb = 19.0921883092
Median: mc = 19.0921883092

Inradius: r = 6.56882040428
Circumradius: R = 13.34549224997

Vertex coordinates: A[24; 0] B[0; 0] C[9.18875; 18.8843586623]
Centroid: CG[11.06325; 6.29545288743]
Coordinates of the circumscribed circle: U[12; 5.83884035936]
Coordinates of the inscribed circle: I[10.5; 6.56882040428]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 128.1111040455° = 128°6'40″ = 0.90656331895 rad
∠ B' = β' = 115.9444479772° = 115°56'40″ = 1.1187979732 rad
∠ C' = γ' = 115.9444479772° = 115°56'40″ = 1.1187979732 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.