Not good with these types of questions anyone good at this ? !

Now, notice the picture below

is really just one rectangle and a circle, well, half a circle or a semi-circle

so.... if you get the area of the whole rectangle, 16*19
and subtract, the area of half the circle, you end up with the shaded area

since, what you'd be leftover is, the rectangle, with a semi-circular hole, that was subtracted



now... let's say, you  get an amount of hmmm [?]
ok, how much is that in percentage? well, 16*19 is 304

so, if we take 304 as the 100%, how much is [?] in percentage?



solve for "x"

The answer would be 24mm