# 18 22 28 triangle

### Acute scalene triangle.

Sides: a = 18   b = 22   c = 28

Area: T = 197.909907003
Perimeter: p = 68
Semiperimeter: s = 34

Angle ∠ A = α = 39.98331214543° = 39°58'59″ = 0.69878371146 rad
Angle ∠ B = β = 51.75333801217° = 51°45'12″ = 0.90332668822 rad
Angle ∠ C = γ = 88.26334984241° = 88°15'49″ = 1.54404886568 rad

Height: ha = 21.998989667
Height: hb = 17.99217336391
Height: hc = 14.1366362145

Median: ma = 23.51659520326
Median: mb = 20.80986520467
Median: mc = 14.42222051019

Inradius: r = 5.82108550009
Circumradius: R = 14.00664323458

Vertex coordinates: A[28; 0] B[0; 0] C[11.14328571429; 14.1366362145]
Centroid: CG[13.04876190476; 4.7122120715]
Coordinates of the circumscribed circle: U[14; 0.42444373438]
Coordinates of the inscribed circle: I[12; 5.82108550009]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 140.0176878546° = 140°1'1″ = 0.69878371146 rad
∠ B' = β' = 128.2476619878° = 128°14'48″ = 0.90332668822 rad
∠ C' = γ' = 91.73765015759° = 91°44'11″ = 1.54404886568 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.