Class 8 Maths Part 2 Chapter 3, Proportional Reasoning–2, extends Part I’s ratio work to map scales, multi-term ratios (a : b : c), pie charts (circle graphs) and inverse proportions.
What Class 8 Maths Chapter 3 Covers
3.1 Quick Recap, 3.2 Ratios in Maps, and 3.3 Ratios with More than 2 Terms apply scale factors to maps and combine two-term ratios into multi-term ratios such as a : b : c.
3.4 Dividing a Whole in a Given Ratio and 3.5 A Slice of the Pie split quantities across multiple shares and convert proportional parts into central angles (out of 360°) to construct pie charts.
3.6 Inverse Proportions contrasts direct proportion (y/x = k) with inverse proportion (x × y = k), such as speed vs travel time or number of workers vs days taken.
Exercises in Chapter 3
- Figure it Out exercise sets throughout the chapter with real-world applications and puzzles.
Read Class 8 Maths Chapter 3 Online
More Chapters
- Previous: Chapter 2: The Baudhāyana-Pythagoras Theorem
- Next: Chapter 4: Exploring Some Geometric Themes
- All Maths chapters and the other Class 8 books: Class 8 NCERT books 2026-27
- All Class 1 to 12 NCERT Textbooks: NCERT Books PDF (Class 1–12)
- Every book chapter by chapter: NCERT chapter wise PDF
FAQ
How do you find the angle of a sector in a pie chart?
Divide the category’s value by the total value and multiply by 360°.
When are two quantities in inverse proportion?
When multiplying one quantity by a factor k causes the other quantity to be divided by the same factor k, so their product remains constant (x × y = constant).