Pleaseee helppp Which of the following uses a variable to represent a person, place, or thing
that is unknown?

A. a C-sharp on the piano

B. apartment 12A

C. a B+ grade

D. Mr. X

D.

Step-by-step explanation:

All of them could represent something or someone, but Mr. X is the closest because X is usually used as a variable.

proportions are fractions that equal to each other. so if two fractions are the same, they are proportional.

let's check the answers to see if they are proportional.

question a is not proportional because you can't turn 1.5/3 to 3/9. if you try to multiply 1.5/3 by 2 or 3, you wont get 3/9. it's impossible to make the fractions the same.

question b is not proportional because you can't turn 22/33 to 4/6. 33 can't go into 6.

question c is proportional because when you multiply 2 and 3 by 71, you would get 142/213, and those fractions equal to each other

question d is proportional because when you divide 14 and 7 by 2, you would end up with 7/3.5, and those fractions equal to each other.