Master Chapter 7 Class 8 - Proportional Reasoning-1(Ganita Prakash) with comprehensive NCERT Solutions, Practice Questions, MCQs, Sample Papers, Case Based Questions, and Video lessons.
Start Learning NowWelcome to Chapter 7, Proportional Reasoning-1, from your Class 8 Maths book, Ganita Prakash.
This chapter is built around a single, powerful idea that you see every day: how do things change together?
It all starts with a simple, modern example: resizing a digital picture. Why is it that when you drag one corner of a photo, it scales up perfectly, but if you just pull one side, the image looks stretched and distorted?
The answer is proportional reasoning. The "good" resize keeps the relationship, or ratio, between the image's width and height exactly the same. The "bad" resize breaks that relationship.
This chapter will give you the mathematical tools to understand and control these kinds of relationships.
Ratios: First, we'll master the ratio. A ratio, written as a:b, is simply a way to compare two quantities. In our example, it's the ratio of the tiger's width to its height.
Proportion: This is the key concept. We'll learn that when two ratios are equal, they are in proportion. This is the mathematical secret to the "good" resize: the new width-to-height ratio is in proportion to the original width-to-height ratio.
Solving Problems with Proportion: You'll learn how to use this reasoning to solve all kinds of practical problems. For example, you'll learn the method for dividing a whole quantity into parts based on a given ratio (like splitting ₹1000 between two people in the ratio of 2:3).
Understanding proportion is a fundamental life skill, used in everything from cooking (scaling a recipe up or down) to reading maps. At Teachoo, we break down these concepts with clear, visual examples to help you see how this "proportional reasoning" works everywhere.
To begin, please click on any topic link to get started.