The shaded area is just the area that is common between both circles.

The difference between the unshaded areas of the circles is the same as the difference between the areas of the full circles.

It is unchanged when you cut away the shaded area from both circles.

So just subtract the area of the smaller circle from the bigger circle.






For example, let's say circle Q's area is 100cm², circle P's area is 80cm² and shaded area is 20cm².

Difference in areas of the full circles
= 100cm² - 80cm²
= 20cm²


Unshaded area of Q
= 100cm² - 20cm²
= 80cm²

Unshaded area of P
= 80cm - 20cm²
= 60cm²


Difference in unshaded areas
= 80cm² - 60cm²
= 20cm²

Oh I see! Thank you for your detailed explanation. Appreciated :)

Welcome