The vertices of a triangle are (5, 1),
(11, 1) and (11, 9). Find the co-ordinates of
the circumcentre of the triangle.
Answers
Vertices of the triangle are A(5,1), B(11,1) and C (11,9). Let P(x, y) be the circumcenter of the triangle.
So, PA = PB = PC (Circumcenter is equidistant from the vertices of the triangle)
=>(PA)2 = (PB)2
=>{(x – 5)2 + (y – 1)2} = {(x –11)2 + (y - 1)2}
= {(x –11)2 + (y - 1)2}=>x2 + 25 – 10x + y2 + 1 – 2y = x2 + 121 – 22x + y2 + 1 - 2y
=> 12x = 96
=> x = 8_______(1)
(1) As,(PA)2 = (PC)2=>{ (x –5)2 + (y – 1)2 } = { (x – 11)2 + (y - 9)2 }=> x2 + 25 – 10x + y2 +1 –2y = x2 + 121 – 22x + y2 + 81 - 18y=> 25+1 -10x-2y = 121+81-22x -18y
=> 26-10x-2y= 202 -22x-18y
=> 22x-10x +18y-2y = 202 -26
=> 12x +16y = 276 .....(using 1)
=> 16y = 276-96=> 16y = 180
y = 180/16
=>y = 45/4
Step-by-step explanation:
Vertices of tge triangle are A (5 , 1 ) , B ( 11 , 1 ) , C ( 11 , 9 )
Let P (x,y) be the circumference of the triangle
So, PA = PB = PC ( circumference is the equidisant from the vertices of the triangle )
---------> (PA)2 =( PB )2
----------> €(X - 5 )2 + (Y - 1 ) 2 )
= X2 + 25 - 10x + y2 + 1 - 2y = X2 + 121 -22x +y2+1 - 2y
««12x = 96
therefore , x = 8 ..............(1)
As ,( PA )2 = (PC)2
««€(x - 5) 2 + (y - 1 ) 2 ))= €(x - 11)2 + (y - 9)2)
### X2 + 25 - 10x + y2 +1 - 2y = X2 + 121 - 22x + y2 + 81 - 18y
= 25 +1 - 10x - 2y = 121 + 81 - 22x - 18y
= 26 - 10x - 2y = 202 - 22x - 18y
= 22x - 10x + 18y - 2y = 202 - 26
= 12x + 16y = 276
= 12(8)+ 16y = 276 (using 1)
= 16 + 16y = 276
= 16y = 276 - 16
= 16y = 180
Therefore :
y = 180/16
and , y= 45/ 4