Explanation:
Quadrants 2 and 3 houses points that have negative x-values, while as Quadrants 1 and 4 houses points that have positive x-values.
If 'your sister' completes the text with negative y-value, the point would be in Q3.
If 'your sister' completes the text with positive y-value, the point would be in Q2.
All you have to do is multiply the top and bottom by the same number (I'll do two). 5 times 2 = 10, and 8 times 2 = 16. 10/16 is equivalent to 5/8. A proportion for this can be written as 5/8 = 10/16.
The area of the new square is 9k. For example if in the original square, each side was 2, then k=4. 2*3=6 so each side would be 6 long. 6*6 is 36 so the new square's area is 9 times the original.