1. 2º ESO UNIDAD 4. PROPORCIONALIDAD
1. RAZÓN ratio /ˈreɪʃɪˌəʊ/
Ratios can be written in several different ways.
Ratio of squares to circles is 3/6 3:6 3 to 6 0,5
¿And ratio of circles to squares?
Part-to-Part:
The ratio of boys to girls is 2:3 or 2/3
The ratio of girls to boys is 3:2 or 3/2
Part-to-Whole:
The ratio of boys to total pupils is 2:5 or 2/5
The ratio of girls to total pupils is 3:5 or 3/5
2. 2º ESO UNIDAD 4. PROPORCIONALIDAD
To write a ratio in its simplest form we divide both sides by their highest common factor (just as we
divide the top and bottom of a fraction).
For example:
3 / 6 becomes 1 / 2 =
12 / 15 becomes 4 / 5 =
The ratio of sheep to goats at the country was 5 to one or 5 / 1
3. 2º ESO UNIDAD 4. PROPORCIONALIDAD
Sizes
When shapes are "in proportion" their relative sizes are the same.
Here we see that the ratios of head length to body length are the same in both drawings.
So they are proportional.
Making the head too long or short would look bad!
