Question

how to inscribe a semi circle in a square so that it touches all 4 sides

Answer 1

for drawing a circle in the squre which touches the all four boundry:--
1 - first u have to knoiw the side value of square in units.
2 - then,you open compass in half of  side of square.
3-  then u draw circle put point of compass in centre of square and see that the circle touches all the four boundry.
                                            plz mark it best

Answer 2

An inscribed semi-circle cannot touch all the four sides of a square.  It can touch at most 3 sides of a square.   You need to draw at least 3/4 th of the inscribed circle to touch all the four sides.

TO draw a full inscribed circle inside a square:
 
   1. Mark the mid points E, F, G and H respectively of the sides AB, BC, CD, and DA of the square.
   2. Join the mid points of the opposite sides, ie., draw EG and FH.
   3. Mark the intersection of EG and FH as the center O of square.
   4. Now draw a circle with the center O and radius EO or HO or GO or FO.
   5. The inscribed circle will touch the sides exactly at E, F, G and H.

You can draw the inscribed circle between E, F, G and H, and stop at H. Then it is drawn to 3/4th of total, but it touches all four sides.