A lake has an area of 63 800000 000 square metres. Write this area in square kilometres, correct to 2 significant figures.

63,800,000,000 square metres equals 63,800 square kilometres

Step-by-step explanation:

The rule of three or is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them. That is, what is intended with it is to find the fourth term of a proportion knowing the other three.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other), the direct rule of three must be applied. To solve a direct rule of three, the following formula must be followed:

a ⇒ b

c ⇒ x

Being a, b and c the known numbers and x the unknown variable to be calculated you have:

In this case, knowing that 1 square meter equals 1*10⁻⁶ square kilometers, the rule of three applies as follows: if 1 square meter equals 1.0 * 10-6 square kilometers, 63,800,000,000 square meters to how many square kilometers is it?

Area= 63,800 square kilometres

63,800,000,000 square metres equals 63,800 square kilometres

area = length x width

length = 2 x width

32 = 2 x width x width

32 = 2 x width^2

36 = width ^2  

width = 6

length = 12

area is 32

perimeter = 2 x 12 + 2 x 6 = 24 + 12 = 36

step-by-step explanation: