Although the side of square A is 50% of the side of square B, if you think about things logically here square A is only 25%of square B. Therefore the shaded area HAS to be half of 25% making the answer 12.5%
Lets start by giving both of the square's lengths a value. So if B's length was 10cm long, and A is 50% of B, then A's length will be 5cm long. Now to workout the area-
Formula to calculate the area of a square= side x side
A= 5 x 5=
B= 10 x 10=
To find the percentage of area A out of B, put the areas in a fraction=
You can straight away see that A is 25% of B since the fraction is out of a 100.