y
30
A B C
D
E
O 30 x
( b ) ( i ) Find DE .
( ii ) Hence , find ˆ DOE in radians .
( iii ) Write down BOD ˆ in radians .
[ 5 ] The straight line BD is the boundary of the Voronoi cells of C ( 30 , 30 ) and F , where F is the site of the region OBD .
( c ) ( i ) State the geometric relationship between BD and CF .
( ii ) Find the coordinates of the mid-point of BD .
( iii ) Hence , write down the coordinates of F .
The owner can walk along OA , ABC , CDE , OE , OB , OD and BD . One scarecrow is placed at each of the six positions O , A , B , C , D and E .
[ 5 ]
© SE Production Limited 3 All Rights Reserved 2021