Step 1: Define common-size statements.
In common-size statements, each item is expressed as a percentage of a common base:
- In Balance Sheet → percentage of total assets/liabilities.
- In Profit & Loss A/c → percentage of net sales.
Step 2: Why percentage?
The objective is to make comparison easy by converting absolute figures into relative percentages. Ratios are used separately in ratio analysis, not in common-size statements.
Step 3: Conclude.
Thus, common-size statements are prepared in the form of percentage.
Final Answer:
\[
\boxed{\text{Percentage}}
\]