Numbers in Nature and LifeGCNU 1025

Numbers Save the Day

Numbers in photo sizes

• Measurement of pixel density of photo:• ppi/dpi: pixels per inch/dots per inch• Example: 4 inches x 6 inches photo with 300 ppi

• Total number of pixels: 1200 pixels x 1800 pixels• Example: 5 inches x 7 inches photo with 300 ppi

• Total number of pixels: 1500 pixels x 2100 pixels

Numbers in photo sizes

• Different aspect ratios: distortion in change of size

Numbers in paper size

• A series: distortion free in shrinking 2 pages into 1• What should the aspect ratio be (to achieve that)?• What should x/y be to avoid distortion in scaling?

Numbers in paper size

• A series: distortion free in shrinking 2 pages into 1• What should the aspect ratio be (to achieve that)?• What should x/y be to avoid distortion in scaling?

• should be to avoid distortion

Numbers in paper size

• A series: height to width ratio of to avoid distortion• A0: biggest• A1: area half of that of A0

• Longer side of A1 same as shorter side of A0• A2: area half of that of A1

Numbers in paper size

• B series: same aspect ratio as A-series (distortion-free)• B4: A3.5 (bigger than A4 but smaller than A3)• B0: biggest

• B1: area half of that of B0• Longer side of B1 same as shorter side of B0

Numbers in paper size

• B series: same aspect ratio as A-series (distortion-free)• B4: A3.5 (bigger than A4 but smaller than A3)

• Geometric mean used

Numbers in paper size

• B series: same aspect ratio as A-series (distortion-free)• B4: A3.5 (bigger than A4 but smaller than A3)

• Geometric mean used• Example:

• Shorter side of B4 is the geometric mean of shorter sides of A3 and A4:

Numbers in Nature and Life

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