1
| sketch circle ray1 ray2 tangent1 tangent2 points angle radius innerPolygon outerPolygon computePolygons|
2
sketch := DrGeoSketch new.
4
circle := sketch circleCenter: 0@0 radius: radius.
5
circle large color: Color red.
6
computePolygons := [ ].
8
computePolygons := [:sides |
9
angle := Float twoPi / sides.
10
points ifNotNil: [ points do: [ :point | sketch domain deleteMathItem: point mathItem ] ].
11
points := Array new: sides.
12
points at: 1 put: (sketch point: radius@0) hide.
14
points at: i put: (sketch rotate: (points at: i - 1) center: 0@0 angle: angle) hide].
15
ray1 := (sketch ray: 0@0 to: (sketch middleOf: points first and: points second) hide) dotted.
16
tangent1 := (sketch perpendicular: ray1 at: (sketch altIntersectionOf: circle and: ray1) hide) dotted.
17
ray2 := (sketch ray: 0@0 to: (sketch middleOf: points second and: points third) hide) dotted.
18
tangent2 := (sketch perpendicular: ray2 at: (sketch altIntersectionOf: circle and: ray2) hide) dotted.
19
outerPolygon := sketch
20
regularPolygonCenter: 0@0
21
vertex: (sketch intersectionOf: tangent1 and: tangent2) hide
23
innerPolygon := (sketch regularPolygonCenter: 0@0 vertex: radius@0 sides: sides) opaque color: Color white.
25
text: (String streamContents: [:s |
26
s nextPutAll: 'Sides: '; print: sides; cr;
27
nextPutAll: ((innerPolygon mathItem length / (2 * radius)) printShowingDecimalPlaces: 4);
28
nextPutAll: ' < π < ';
29
nextPutAll: ((outerPolygon mathItem length / (2 * radius)) printShowingDecimalPlaces: 4)])
33
3 to: 20 do: [ :mySide |
34
computePolygons value: mySide.
36
(Delay forMilliseconds: 500) wait].
added
removed
resources/SmalltalkSketches/Archimedes PI Interval.st
