# 20 26 28 triangle

### Acute scalene triangle.

Sides: a = 20   b = 26   c = 28

Area: T = 249.5421579702
Perimeter: p = 74
Semiperimeter: s = 37

Angle ∠ A = α = 43.27991752006° = 43°16'45″ = 0.75553641048 rad
Angle ∠ B = β = 63.02769449584° = 63°1'37″ = 1.1100027707 rad
Angle ∠ C = γ = 73.6943879841° = 73°41'38″ = 1.28662008418 rad

Height: ha = 24.95441579702
Height: hb = 19.19655061309
Height: hc = 17.82443985501

Median: ma = 25.1099800796
Median: mb = 20.56769638012
Median: mc = 18.49332420089

Inradius: r = 6.7444367019
Circumradius: R = 14.58767474445

Vertex coordinates: A[28; 0] B[0; 0] C[9.07114285714; 17.82443985501]
Centroid: CG[12.35771428571; 5.94114661834]
Coordinates of the circumscribed circle: U[14; 4.09655098594]
Coordinates of the inscribed circle: I[11; 6.7444367019]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 136.7210824799° = 136°43'15″ = 0.75553641048 rad
∠ B' = β' = 116.9733055042° = 116°58'23″ = 1.1100027707 rad
∠ C' = γ' = 106.3066120159° = 106°18'22″ = 1.28662008418 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.