Yes
A4 paper size is 8.3in × 11.7in.
European size paper
A4 paper measures 8.27 x 11.69 inches.
Half of A4 is A5.
Two full A4 size papers
1mm
A4 paper is exactly half the size of A3, and they both have the same aspect ratio. So A4 --> A3 is an enlargement. Most photocopiers use A4 as standard. You need a larger photocopier to copy onto A3. The photocopier will usually offer A4 --> A3 as an option.
The size of the paper should be an A4 paper.
The measurements of a size A4 paper are 11.7 x 8.3 inches or 297 x 210 millimeters. It is just a little bigger than the standard letter size of paper.
No, Australia is one of the few countries in the world that use A3 as their standard format size. Even if it does, A3 and A4 are all part of the A series paper sizes defined by ISO 216.
A3.
A quarter of an A4 sheet of paper is typically referred to as a quarter sheet or quarter page. It is a common measurement used in printing and design to indicate a smaller portion of a standard A4 size paper.