Explanation:
1. use the circumfrence equation which is 2pi*r
2 8 is the radius and r in the equation is the radius so we have 2pi*8= 16*pi
3. now find the arc of XY which is (16*pi)/(4) this equals 4pi
4. know that we know that one fourth around the circle is 4pi since arc XPY equals XY 3 times so arc XPY equals (4pi)*3 which equals to 12pi
5. so arc XPY equals 12pi