If 54 makes up 25 percent, then x makes up 100 percent. Using this phrase we can write a proportion or use equivalent fractions.
54/25= x/100
A whole is 100 percent and we know 25 percent. Then it is simple to go from 25 percent to 100 percent. Simply multiply 25 times 4 to get 100 percent. Since we multiplied the denominator by four, then we have to multiply the numerator (54) by 4. 54 times 4 is 216.
This means that 1/4 of the books in the library is 54, so just multiply 54 by 4, which gives you 100%, or all of the books. 54 times 4 is equal to 216, so there are 216 books in the library.
