Exercise 1.2 Practice
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Overview
This page provides comprehensive Ch 1: The Use of Coordinates - Exercise 1.2 Practice. Free NCERT Solutions for Class 9 Maths. Learn how to describe positions on a plane and calculate distances.
Coordinate Applications & Distance
Q1: Table Mapping
How will you describe the position of a study lamp on your study table to another person?
Consider the table as a 2-D plane. Choose two perpendicular edges of the table as axes.
Measure the distance of the lamp from the longer edge (say 25 cm) and the shorter edge (say 15 cm).
The position can be described as the ordered pair $(25, 15)$ or $(15, 25)$ depending on the axes chosen.
Using an ordered pair of distances from two perpendicular edges.
Q2: City Streets
A city has two main roads which cross each other at the centre of the city. These two roads are along the North-South direction and East-West direction. All other streets of the city run parallel to these roads and are 200 m apart. There are about 5 streets in each direction.
How many cross-streets can be referred to as $(4, 3)$?
How many cross-streets can be referred to as $(4, 3)$?
In a coordinate system, an ordered pair $(x, y)$ represents a unique point where two specific lines intersect.
Street 4 in the E-W direction and Street 3 in the N-S direction will intersect at only **one** point.
Only one cross-street.
Q3: Distance Formula
Find the distance between the origin $(0, 0)$ and the point $(6, 8)$.
Using distance formula: $d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}$
$d = \sqrt{(6 - 0)^2 + (8 - 0)^2} = \sqrt{6^2 + 8^2}$
$d = \sqrt{36 + 64} = \sqrt{100} = 10$.
10 units