ABCD is a parallelogram on xy rectangular coordinate plane, three of the four vertices of parallelogram are (5,15) , (5,30) and (-5,15). Which can be the coordinate of fourth vertex?
Choices:
A) (-5,-5)
B) (5,15)
C) (-5,-30)
D) (-5,10)
E) (15,30)
A(-5, 15)   B(5, 15)   C(5, 30)   X(-5, 30): Parallelogram=Square=AXCB, where AX||CB, AX=CB, XC||AB, XC=AB   Y(-5, 5): Parallelogram=AYBC, where AY||BC, AY=BC, AC||YB, AC=YB   Z(15, 30): Parallelogram=ACZB, where AC||ZB, AC=ZB, CZ||AB, CZ=AB   Ans:(15,30)
<result>E</result>
ABCD is a parallelogram on xy rectangular coordinate plane, three of the four vertices of parallelogram are (5,15) , (5,30) and (-5,15). Which can be the coordinate of fourth vertex?