How do you convert $ 0.9 $ into percent and fraction?

Hint: In order to calculate percentage multiply the given number with 100 and to convert into fraction divide the number with 10 raised to the power no of digits after decimal and remove decimal point.
Formula Used:
 $ p = n \times 100 $
Here p is the percentage , n is the decimal number.

Complete step-by-step answer:
Given a decimal number $ 0.9 $ .
So in order to convert any decimal number into percent multiply it with 100 and add % symbol in the end
Here our decimal number is $ 0.9 $
 $
   = 0.9 \times 100 \\
   = 90\% \;
  $
Therefore decimal number $ 0.9 $ in percent is $ 90\% $
So, the correct answer is “$ 90\% $”.

Now to Convert $ 0.9 $ in to decimal divide $ 0.9 $ with 10 raised to the power 1 as there is 1 digit after decimal and remove decimal point
 $
   = 0.9 \\
   = \dfrac{9}{{10}} \;
  $
So, the correct answer is “$\dfrac{9}{{10}} $”.

Note: Alternative:
 If you don’t want to multiply, we have another way to calculate percentage i.e. by moving the decimal point 2 places in the right
For example: Calculate 0.9 into percentage
Decimal number =0.9
Now ,move the decimal point two places towards the right and add $ \% $ at the end of the result.
 $ = 90\% $