Consider a quarter of a circle of radius 36. Let r be the radius of the circle inscribed in this quarter of a circle. Find r.
Choose one:  A) 16*(sqr2 -1)  B) 8*(sqr3 -1)  C) 4*(sqr7 - 1)  D) 36* (sqr2 -1)  E) None of these
I got 36/(sqr2 +1) and just forgot to multiply by (sqr2 -1).   Answer is 36* (sqr2 -1)
<result>D</result>
Consider a quarter of a circle of radius 36. Let r be the radius of the circle inscribed in this quarter of a circle. Find r.