1a
P(-5/2,9/2)=(-2.5,4.5)
Q(1/2,3/2)=(0.5,1.5)
R(5/2,7/2)=(2.5,3.5)
S(-1/2,13/2)=(-0.5,6.5)
bi
PS^2-QR^2=(-2.5-(-0.5))^2+(4.5-6.5)^2-(2.5-0.5)^2-(3.5-1.5)^2
=(-2)^2+(2)^2-(2)^2-(2)^2
=0
i.e. PS^2=QR^2
PS=QR
PQ^2-SR^2=(-2.5-0.5)^2+(4.5-1.5)^2-(-0.5-2.5)^2-(6.5-3.5)^2
=(-3)^2+(3)^2-(-3)^2-(3)^2
=0
PQ=SR
bII
slope of PS: (4.5-6.5)/(-2.5-(0.5))=2/3
PQ: (1.5-4.5)/(0.5-(-2.5))=-3/2
SR: (-0.5-2.5)/(6.5-3.5)=-1
QR: (2.5-0.5)/(3.5-1.5)=1
(slope of PS)(slope of PQ)=-1
(slope of QR)(slope of SR)=-1
Therefore,
PS丄PQ and QR丄SR