1. Let's start by stating the problem: Understanding ratio and proportion as explained in the 'The Leading' maths book for class eight. 2. A ratio is a comparison of two quantities by division. It is written as $a:b$ or $\frac{a}{b}$ where $a$ and $b$ are numbers. 3. Important rule: Ratios must compare quantities of the same kind (e.g., length to length, apples to apples). 4. Proportion states that two ratios are equal. If $\frac{a}{b} = \frac{c}{d}$, then $a$, $b$, $c$, and $d$ are in proportion. 5. To solve proportion problems, use cross multiplication: $a \times d = b \times c$. 6. Example: If $\frac{2}{3} = \frac{x}{9}$, then cross multiply to get $2 \times 9 = 3 \times x$. 7. Simplify: $18 = 3x$. 8. Solve for $x$: $x = \frac{18}{3} = 6$. 9. So, the value of $x$ is 6. This method helps solve many ratio and proportion problems by comparing and finding unknown values.