The expression \( \frac{3}{4} \times \frac{1}{2} \) represents a situation where you are taking a fraction of a fraction. Specifically, it shows that you have a certain quantity (in this case \( \frac{3}{4} \)) and you are finding \( \frac{1}{2} \) of that quantity.
Looking at the options:
A. Susan had \( \frac{3}{4} \) of a liter of orange juice in a carton. She poured \( \frac{1}{2} \) of it into a jar. How much of a liter did Susan pour into the jar?
- This situation matches \( \frac{3}{4} \times \frac{1}{2} \), because you find \( \frac{1}{2} \) of \( \frac{3}{4} \) liter.
B. Mrs. Carter has a package of butter that weighs \( \frac{3}{4} \) of a kilogram. She uses \( \frac{1}{2} \) of a kilogram of butter for baking. How much of the butter did Mrs. Carter use?
- This situation does not match, as it involves using \( \frac{1}{2} \) kg directly, rather than a fraction of \( \frac{3}{4} \).
C. Chris bikes for \( \frac{3}{4} \) of an hour. He stops for a rest and then bikes for another \( \frac{1}{2} \) of an hour. How many hours did Chris bike in all?
- This situation involves addition rather than multiplication, so it does not match.
D. Tony takes \( \frac{3}{4} \) of an hour to mow his lawn. He has already spent \( \frac{1}{2} \) of an hour mowing. How much longer will Tony take to mow all of the lawn?
- This is also not a match, as it deals with figuring out how much time is left rather than determining a fraction of a fraction.
Therefore, the correct choice is A:
Susan had \( \frac{3}{4} \) of a liter of orange juice in a carton. She poured \( \frac{1}{2} \) of it into a jar. How much of a liter did Susan pour into the jar?