Refer to the attached image.
As we can observe ABCD is a square, whose corners that is A,B,C and D lie on the circle.
The diameter AC = 0.35 meter.
We have to find the side of square.
Let the measure of side of a square be 'l' meter
In triangle ABC,
By Pythagoras theorem, we get





So, l = 0.25 meter
Therefore, the measure of side of the square is 0.25 meter.