Which sentence best states the main idea?

A-series paper applies an exact geometric ratio through rounded real-world dimensions (The passage distinguishes the exact ideal from the close, practical dimensions used for real sheets.)

Why can a copier use one scale factor between neighboring A sizes?

The ideal proportions repeat when the sheet is halved (Because the ideal shape repeats, scaling changes size without changing proportions.)

In this passage, “nominally” means

by its stated standard or name, though a physical measurement may vary slightly (The text contrasts the nominal one-square-meter standard with a physical object and tolerances.)

What is the theoretical area of an A0 sheet?

One square meter (The second paragraph gives one square meter as the theoretical A0 starting area.)

A Sheet That Nearly Keeps Its Shape: Level 3 Reading Comprehension Questions

Fold an A4 sheet in half across its long side and the smaller rectangle is nearly the same shape as the whole. The A-series is based on an ideal ratio: the long side divided by the short side equals the square root of two, about 1.414. This is the one rectangular proportion that returns after exact halving.

The ideal rule creates a family of related sizes. A design can shrink from a poster to a flyer without changing proportions, and a copier can use one scale factor between neighboring sizes. The theoretical starting sheet, A0, has an area of one square meter. Each later size has half the preceding area.

Physical paper uses whole-millimeter dimensions and manufacturing tolerances. An A4 sheet is listed as 210 by 297 millimeters, so its measured ratio is close to, not exactly, the mathematical value. A physical A0 sheet is likewise nominally one square meter rather than a perfect geometric object.

The distinction does not weaken the standard. It explains how standards connect an exact idea with objects that must be cut and measured in the real world. North American letter paper uses a different proportion, so halving it does not preserve even the ideal shape. A small mathematical choice can simplify a large system of paper, printing, and machines.

Comprehension questions