GMAT Prep / Geometry Circle

This topic has expert replies
Source: — Problem Solving |

Master | Next Rank: 500 Posts
Posts: 145
Joined: Thu Nov 13, 2008 7:18 am
Location: United Kingdom
Thanked: 5 times

by poonam1279 » Sun Dec 07, 2008 11:40 am
medallion=circular piece of coloured glass+metal frame
radius of medallion(complete circle)=r metal frame width=s
circle area =pi * r^2
inner circle area=pi * (r-s)^2
frame area= circle area- inner circle area
=pi * r^2- pi* (r-s)^2
= pi * (r^2) - pi * (r^2-2rs+s^2)
= pi* 2rs-pi*s^2
=pi*s(2r-s)