Geometry of Straight lines - Lesson 1

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Starting again with the homework of yesterday:

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Today's lesson: Geometry of straight lines

Geometry of mathematics is size, shape and position of figures and their location in space.

This lesson will focus on the building blocks of geometry.

When working with geometric figures we can learn three things about each of them,

  • What the definition is
  • What the figure looks like and
  • How to name them

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Explain the terminology to the learners

The first geometric figure you are going to learn about is the point.

A point is a definite place in space that doesn't have a size or shape.

An example of a point:

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A ray:

A ray has and end point but it extends in ONE direction indefinitely
We can say that a ray has a definite starting point but no definite ending point

Picture of a ray:

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Note that this ray has 2 points, Point G on the line and point F which is the starting point of the line.

To name the ray, we use the letters of the two points and a symbol.

The symbol looks like a small ray above the letters.

Line segment:

A line segment has a definite starting and a definite ending point.
It is a set of connected points.

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Line
A line has 2 arrows on each end, but the line does not end because of the arrows.
It goes on indefinitely.

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Activity 1
Say whether the following is a point, ray, line segment or a line.

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Activity 2

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