Slope Of A Line
Chapter Name : Straight Lines |
Sub Topic Code : 104_11_10_02_04 |
Topic Name : Slope Of A Line |
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Sub Topic Name : Angle Between Two Lines |
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Introduction
Two lines in a plane can be parallel or intersecting. When the lines intersect they make pairs of vertically opposite angles such that sum of two adjacent angles is 180°
Pre-Requisites:
Idea about slope of a line, parallel and intersecting lines.
Real Life Question:
There are two inclined poles on the road side; slope of one pole is double the slope of other pole. If the angle between them is 18°, what are the inclinations of the poles.
Key Words / FlashCards
| Key Words | Definitions (pref. in our own words) |
|---|---|
| Angle between two lines | Let L1 and L2 be two intersecting lines with slopes m1 and m2 respectively. Then the angle between those lines is given by: ?=tan^(-1)?((m_2-m_1)/(1+m_1 m_2 )) |
Learning aids / Gadgets
| Gadgets | How it can be used |
|---|---|
| Protractor | Draw two intersecting lines on the graph. Measure the inclination of both the lines with x-axis. Now confirm the result with the formula. |
Real life uses :
Engineers use angles to draw geometric figures. Railway tracks are made by measuring of angles between the lines.
Practical examples around us
| Examples | Explainations |
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What you learn in Theory:
What are intersecting lines and angle between two lines?
What you learn in Practice:
How to find the angle between two intersecting lines when the inclination of both the lines in known?