THE reason is a concept that comes from Mathematics and is directly related to quantification. Characterized by the division operation, it is structured by a numerator and a denominator. Look:
The → numerator
b → denominator
*b must always be nonzero.
The reasons can relate the same or different quantities. Understand by magnitude measures such as meter, second, liter, hour, kilometer, among many others. Average speed and population density are examples of ratio calculations that involve different quantities. Let's see in detail how each of them is carried out:
The calculation of the average speed can be found in the contents of Physics it's from Chemistry. Understand average speed such as reason between distance traveled and time:
Vm = d
t
Vm = Average Speed;
d = Distance covered. The distance can be measured in km (kilometer) or in m (meter);
t = time. Time can be given in h (hours) or s (seconds).
Already the calculation of demographic densitycan be found in the content of Geography. This reason is given by the ratio of the number of inhabitants (Population) and the occupied area.
dd = Pan
THE
Dd = Demographic density;
Pa = Population. The unit of measure for pollution is hab (inhabitant);
A = Area. The area is measured in km2 (square kilometer).
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To better understand these two reasons, we'll solve two examples:
Example 1
A bullet train travels 286 km from a city THE to a city B and does this journey in 40 minutes. Calculate the average speed of this train during the journey.
Vm =? → This is the value we need to calculate;
d = 286 km;
t = 40 min = 40: 60 = 0.6 h (hour) → We had to convert from minute to hour because, when calculating average speed, the quantities are: km/h (kilometre/hour) or m/s (meter/second).
Vm = d → Vm = 286 km → Vm = 477 km/h approximately.
T 0.6 h
Example 2
The state of Goiás, in the 2014 census, had its population evaluated at 6,523,222 inhabitants. Its area is approximately 340,111,376 Km2. Determine the demographic density of this region and say what that ratio means.
Dd = ?
Pa = 6,523,222 inhab (inhabitants);
A= 340,111,376 Km2 (Square kilometer).
dd = Pan
THE
dd = 6.523.222 hab = 19.17 inhab/km2
340,111,376 Km2
This means that, in one kilometer, there are 19 inhabitants.
By Naysa Oliveira
Graduated in Mathematics
Would you like to reference this text in a school or academic work? Look:
OLIVEIRA, Naysa Crystine Nogueira. "Ratio calculation: average speed and demographic density"; Brazil School. Available in: https://brasilescola.uol.com.br/matematica/calculo-razao-velocidade-media-densidade-demografica.htm. Accessed on June 27, 2021.
