Maths

If you want to see the graph go to
http://hk.knowledge.yahoo.com/question/?qid=7007020701564
1 In the figure,OABC is a rectangle of perimeter 12 units and OC =(二份一)OA.Find the coordinates of A,B and C.
OA+AB+BC+CO=12
2(OA+OC)=12
3OA=12
OA=4
OC=2
SO the coordinates of A,B and C is
A(4,0)
B(4,2)
C(0,2)
2.The figure shows a rectangle of area 45 sq. units. AB = 6 units and the coordinates of A are (3 , -2) . Find the coordinates of B , C and D.
AB *BC=45
6BC=45
BC=9
So
The coordinates of A are (3 , -2)
The coordinates of B are (9 , -2)
The coordinates of C are (9 , 7)
The coordinates of D are (3 , 7)
or
The coordinates of A are (3 , -2)
The coordinates of B are (3 , 4)
The coordinates of C are (12 , 4)
The coordinates of D are (12 , -2)
You jsut see your graph and determine which one is true