# 4 points and distance to middle of square

1. Sep 9, 2008

### th3plan

I forgot, but how can i get distance to middle of a square lets consider sides are all called A. So do i take a^2+a^2=r^2 and 2a^2=r^2 so r= radical(2)r , but since we want half of that i multiply that by 1/2

This correct ?

2. Sep 9, 2008

### HallsofIvy

Staff Emeritus
It would help if you told us what "a" is! Is it the length of each side? If so then, by the Pythagorean theorem, the diagonal has length $\sqrt{a^2+ a^2}= a\sqrt{2}$. Since the middle of the square is at the center of the diagonal, the distance from any vertex to the middle is $a\sqrt{2}/2$