If we have a decimal number and we want to convert it to a fraction, we can start by multiplying (and also dividing) by 10^n, being n the number of decimals of the number.
In this case, 2.16 has 2 decimal places, so we have to multiply and divide it by 10^2=100.
Then, we get:
We already have a fraction: 216/100, but we can try to simplify if looking for common factors:
We have 2^2=4 as common factor between numerator and denominator, so we can simplify the fraction as:
Answer: 2.16 as a fraction is 54/25.