Question

the centre of square abcd is (0,0) and vertex A is (2,1) other vertex is
a) -1,2
b) -2,-1
c) 1,-2
d)-3,-1

Answer 1

Answer:

(5,3)

Let point C(x,y).

Slope of AC=

x+1

y−1

and slope of BD=3x+y−8=0

y=−3x+8→(i)

⇒SlopeofBDis−3

⇒AC⊥BD

⇒

x+1

y−1

×−3=−1

⇒3(y−1)=x+1

⇒3y−3=x+1

⇒3y−x=4→(ii)

Solving equation (i) and (ii)

⇒

20

x

=

20

y

=

20

1

∴x=2,y=2

⇒then,byusingmidformula,

2

x−1

=2,x=5

2

y+1

=2,y=3