# 26 28 30 triangle

### Acute scalene triangle.

Sides: a = 26   b = 28   c = 30

Area: T = 336
Perimeter: p = 84
Semiperimeter: s = 42

Angle ∠ A = α = 53.13301023542° = 53°7'48″ = 0.9277295218 rad
Angle ∠ B = β = 59.49897625939° = 59°29'23″ = 1.03882922285 rad
Angle ∠ C = γ = 67.3880135052° = 67°22'49″ = 1.17660052071 rad

Height: ha = 25.84661538462
Height: hb = 24
Height: hc = 22.4

Median: ma = 25.94222435421
Median: mb = 24.33110501212
Median: mc = 22.47222050542

Inradius: r = 8
Circumradius: R = 16.25

Vertex coordinates: A[30; 0] B[0; 0] C[13.2; 22.4]
Centroid: CG[14.4; 7.46766666667]
Coordinates of the circumscribed circle: U[15; 6.25]
Coordinates of the inscribed circle: I[14; 8]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 126.8769897646° = 126°52'12″ = 0.9277295218 rad
∠ B' = β' = 120.5110237406° = 120°30'37″ = 1.03882922285 rad
∠ C' = γ' = 112.6219864948° = 112°37'11″ = 1.17660052071 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    