Introduction
Chapter Name : Straight Lines |
Sub Topic Code : 104_11_10_01_01 |
Topic Name : Introduction |
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Sub Topic Name : Introduction |
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Introduction
In Analytic geometry, a line in the plane is defined as the set of points whose coordinates satisfy a given linear equation. In a more abstract setting, such as incidence geometry, a line may be an independent object, distinct from the set of points which lie on it. A line segment is a part of a line that is bounded by two distinct end points and contains every point on the line between its end points.
Pre-Requisites:
• Coordinate axes and Coordinate plane • Plotting of points in a plane • Distance between two points • Section formulae
Activity:
Most of the objects we view in daily life that are square/rectangular in shape have edges which can be considered as lines.
Real Life Question:
How do you measure the distance between two points?
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Line | The line is the first species of quantity, which has only one dimension, namely length, without any width or depth, and is nothing other than the flow or run of the point. |
| Line segment | The shortest distance between any two points is called a line segment. The part of a line which lies between two points is called a line segment. |
| Ray | Given a line and any point A on it, we may consider A as decomposing this line into two parts. Each such part is called a ray (or half-line) and the point A is called its initial point. |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Scale | Draw different lines on a coordinate plane. Measure distance between any two points. |
Real life uses :
You have $5,000 in your checking account (0% interest). At the end of each year, you put $10,000 into your checking account. An equation for how much money is in your checking account will be M = 10,000Y + 5,000. The slope (10,000) tells you how much money you make per year. This equation basically represents a line on a graph with slope 10000.
Practical examples around us
| Examples | Explainations |
|---|---|
| Line graphs | Line graphs are used to represent various quantities, patterns, etc to analyze data. |
What you learn in Theory:
Basic concepts about line, plotting a line, finding end points, finding area of a triangle etc.
What you learn in Practice:
Measure distances; solve everyday problems using linear equations that represent lines.