# 16 25 28 triangle

### Acute scalene triangle.

Sides: a = 16   b = 25   c = 28

Area: T = 198.5244400264
Perimeter: p = 69
Semiperimeter: s = 34.5

Angle ∠ A = α = 34.55660777693° = 34°33'22″ = 0.60331173336 rad
Angle ∠ B = β = 62.40881713429° = 62°24'29″ = 1.08992280701 rad
Angle ∠ C = γ = 83.03657508879° = 83°2'9″ = 1.44992472499 rad

Height: ha = 24.81655500329
Height: hb = 15.88219520211
Height: hc = 14.18803143045

Median: ma = 25.30881014697
Median: mb = 19.07222311228
Median: mc = 15.63664957711

Inradius: r = 5.75443304424
Circumradius: R = 14.10440597341

Vertex coordinates: A[28; 0] B[0; 0] C[7.41107142857; 14.18803143045]
Centroid: CG[11.80435714286; 4.72767714348]
Coordinates of the circumscribed circle: U[14; 1.71101172428]
Coordinates of the inscribed circle: I[9.5; 5.75443304424]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 145.4443922231° = 145°26'38″ = 0.60331173336 rad
∠ B' = β' = 117.5921828657° = 117°35'31″ = 1.08992280701 rad
∠ C' = γ' = 96.96442491121° = 96°57'51″ = 1.44992472499 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    