Question

Are the following number in proportion ? [ 2 Marks]
12,15,18, and 20

Answer 1

Step : Finding weather the given numbers are in proportion or not
Given numbers are 12, 15, 18 and 20
If 12 : 15 is equal to 18 : 20 then they are in proportion
Therefore we can find out as follows :
$12:15=18:20$ (1 mark)
$\Rightarrow 12\times 20=15\times 18$
$\therefore Productofextremes=Productofmeans$
$\Rightarrow 240\ne 270$
Therefore,the ratio 12:15 is not equal to the ratio 18:20.
Hence, they are not in proportion. (1 mark)