# 21 24 26 triangle

### Acute scalene triangle.

Sides: a = 21   b = 24   c = 26

Area: T = 237.1422230528
Perimeter: p = 71
Semiperimeter: s = 35.5

Angle ∠ A = α = 49.4770479683° = 49°28'14″ = 0.8633422753 rad
Angle ∠ B = β = 60.30224684279° = 60°18'9″ = 1.05224766211 rad
Angle ∠ C = γ = 70.22770518891° = 70°13'37″ = 1.22656932794 rad

Height: ha = 22.5854974336
Height: hb = 19.7621852544
Height: hc = 18.24217100406

Median: ma = 22.71101298984
Median: mb = 20.35992730715
Median: mc = 18.42655257727

Inradius: r = 6.68800628318
Circumradius: R = 13.81444943341

Vertex coordinates: A[26; 0] B[0; 0] C[10.40438461538; 18.24217100406]
Centroid: CG[12.13546153846; 6.08105700135]
Coordinates of the circumscribed circle: U[13; 4.67333557221]
Coordinates of the inscribed circle: I[11.5; 6.68800628318]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 130.5329520317° = 130°31'46″ = 0.8633422753 rad
∠ B' = β' = 119.6987531572° = 119°41'51″ = 1.05224766211 rad
∠ C' = γ' = 109.7732948111° = 109°46'23″ = 1.22656932794 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.