Let C 1 and C 2 be the centres of the circles x 2 + y 2 - 2 x - 2 y - 2 = 0 and x 2 + y 2 - 6 x - 6 y + 14 =…

Let C1 and C2 be the centres of the circles x2+y2-2x-2y-2=0 and x2+y2-6x-6y+14=0 respectively. If P and Q are the points of intersection of these circles, then the area (in sq. units) of the quadrilateral PC1QC2 is :
  1. 6
  2. 4
  3. 8
  4. 9

Solution

Equation of given circles are

x-12+y-12=4 and x-32+y-32=4.

Hence, C11,1 and r1=2; C23,3 and r2=2

PC1=PC2=2

Now, by distance formula,

C1C2=3-12+3-12=22+22=8

PC12+PC22=C1C22

C1PC2=π2 (by converse of pythagoras theorem in PC1C2)

Hence, area of quadrilateral PC1QC2=2×area of PC1C2=2×area of QC1C2

=2×12×2×2=4

Asked in: JEE Main 2019 (12 Jan Shift 1)

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