Hello,

For someone who doesn't know how to post, I find it wonderful that your title is so clear !

Ok, let's go for it.

Let x be the side of the square (see picture below).

Let's calculate the perimeter in respect with x.

We know that each semicircle is 15cm.

But ! You know that they are semicircles of a circle which diameter is x.

As the perimeter of a semicircle is half the perimeter of the circle :

Hence

~~~~~~~~~~~~

Now, the area !

The area is the sum of the areas of :

- the square

- the 4 semicircles.

You should know the area of the square

So let's see what the area of 1 semicircle is :

The area of a semicircle is half the area of the circle.

Hence , where r is actually

--->

So what is the area of the whole thing ?