Here are some data which you might find useful.
Paper sizes
A4 paper measures \(\quantity{298}{mm}\) by \(\quantity{210}{mm}\).
A3 is double the area of A4 — \(\quantity{298}{mm}\) by \(\quantity{420}{mm}\).
To go from A4 to A3 and from A3 to A2 you double the shorter dimension each time. The sequence continues up to A0.
American Letter size paper is \(\quantity{8.5}{in.}\) by \(\quantity{11}{in.}\).
On Earth
The Shard in London is \(\quantity{309.6}{m}\) high. Its viewing gallery is approximately \(\quantity{244}{m}\) above ground level.
One of the tallest buildings on Earth is the Burj Khalifa in Dubai, at \(\quantity{829.8}{m}\).
The highest mountain is Mount Everest, at \(\quantity{8\,848}{m}\).
In astronomy
The mean distance from the Earth to the moon is \(\quantity{378\,000}{km}\) (from the NASA Moon Fact Sheet).
The mean distance from the Earth to the sun is \(\quantity{149\,600\,000}{km}\) (from NASA Solar System Exploration).
After the Sun, the nearest bright star is Alpha Centauri, at a distance of about \(\quantity{4.4}{light\,years}\) from Earth.
One light year is the distance that light can travel in a year. Light travels at a speed of about \(\quantity{300\,000}{km\,s^{-1}}\).
Andromeda, the closest major galaxy to our own, is approximately \(\quantity{2.5}{Mly}\) from Earth.
\(\quantity{1}{Mly}\) (megalight year) is \(\quantity{10^6}{light\,years}\).
The edge of the known Universe is approximately \(13.8\) billion light years away.
