App Shopper: Circle Equations (Education)

App Activity

Jan 08 '11	Version 2.2
Dec 17 '10	Version 2.1
Nov 03 '10	Version 2.0
Jul 09 '10	Version 1.5
Mar 26 '09	Version 1.4
Jan 07 '09	Version 1.3
Dec 12 '08	Version 1.2
Nov 10 '08	Version 1.1
Oct 16 '08	New App: $.99, v1.0

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Circle Equations

iOS iPhone

Circle Equations is a quick reference guide to finding the center and radius of a circle by completing the square.

It's a companion app to Quadratic Vertex that covers finding the vertex of the graph of a quadratic function and Quadratic Equations that covers the solving of quadratic equations.

Completing the square is the common theme of these apps.

You go step by step through example questions,

- Writing in general form
- Taking constant term to right hand side
- Grouping x related and y related terms
- Completing the squares
- Writing in center-radius form

or go straight to a particular step.

Examples feature equations where the coefficient of x² is equal to one and also where not equal to one.

It's ideal for students as the menu design reinforces each problem solving step.

Examples highlight and simplify algebra that students find hard.

Applications include finding the equation of a tangent line at a a given point on a circle and determining if a given point is inside a circle.