I need help with this question

Ratio: 3/4 : 1/2

We can also write this as:

3/4 / 1/2

Flip the 2nd fraction and multiply:

3/4 * 2/1

Multiply the numerators and denominators together:

6/4

Simplify:

3/2

The first step in answering this is making the fractions have a common denominator.
The LCD for (3/4) and (1/2) is four. 
Since 3/4 already has the denominator, you just need to change 1/2 by multiplying the top and the bottom of the fraction by two.
This gives you (3/4) and (2/4).
Now, you can compare the numerators in this ratio
Numerator of the length/Numerator of the width. This gives you (3/2)
The answer to the question is C, (3/2)

The variables should add up to equal 1