Square
Square and basic formulas for calculating circle. Practically, simply,concisely and graphically.
Notions
 Square is areal planar shape.
 Diagonal is a line which connects opposite corners of square.
Terminology
 a… side of square
 u… diagonal of square
 O… perimeter of square
 P… area of square
Formulas for calculating
Basic formulas
 Perimeter: O = 4 × a
 Area: P = a × a = a2
 Diagonal: u = a × √2 ≈ a × 1,41
Derived formulas
 Side from overall perimeter a = O/4
 Side from lenght of diagonal a = u / √2
 Side from area of square a = √P
 Diagonal from area of square u = √P × √2
 Perimeter from area of square O = 4 × √P
 Area from perimeter of square P = O2 / 16
 Area from lenght of diagonal P = u2 / 2
Circle

Diametr of inscribed circle is equal to lenght of the side of square:
 Inscribed circle: d = a
 Circumscribed circle: D = u
Diametr of circumscribed circle is equal
Practical calculation
Work in progress
Links
References
Related topics
Mathematics a geometry
* Pí
* Čtverec
* Válec
* Koule
Literature
Internet Links
* [http://kruh.wikina.cz/ Obvod kruhu, obsah kruhu] – výpočet online
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