therapyjilo.blogg.se - Compass for geometry class

The key point for discussion is that with constructions, it is possible to investigate geometry without numbers. Conversely, eyeballing where a point or segment should go means that there is no guarantee someone will be able to reproduce it accurately. Tell students that using these moves guarantees a precise construction.

You can mark a point on a line or line segment.

You can set your compass to the length between two marked points and create a circle with that radius centered at any marked point.

You can create a circle centered at a marked point going through another marked point.

You can create a line or line segment between two marked points.

If starting from a blank space, start by marking two points.This display should be posted in the classroom for the remaining lessons within this unit. Make one class display that incorporates all valid moves. The compass makes it easier to make circles, and the straightedge makes it easier to make straight lines.) Ask students, “What is the difference between your attempt in the first question and what you came up with using the straightedge and compass?” (Sample response: Without the tools, it was difficult to make circles and straight lines. The goal is to make sure students understand the straightedge and compass moves that will be allowed during activities that involve constructions and why it is important to agree on standard construction moves.