A triangle has corners at (2 ,4 )(2,4), (6 ,5 )(6,5), and (3 ,3 )(3,3). What is the area of the triangle's circumscribed circle?

1 Answer
Oct 2, 2017

See the answer below...

Explanation:

Suppose the circumcentre of the triangle is (x,y)(x,y)

$1st STEP$
Hence the distance of the point of the circumcentre from the corners of the triangle will be same...
So we can write ,
sqrt((x-2)^2+(y-4)^2)=sqrt((x-6)^2+(y-5)^2)=sqrt((x-3)^2+(y-3)^2)(x2)2+(y4)2=(x6)2+(y5)2=(x3)2+(y3)2
[Squaring each part and removing x^2x2 and y^2y2 from each part]

=>-4x+4-8y+16=-12x+36-10y+25=-6x+9-6y+94x+48y+16=12x+3610y+25=6x+96y+9
Hence we get equations ...
i)i) 8x+2y=418x+2y=41[From 1st and 2nd equation ]
ii) 6x+4y=43ii)6x+4y=43[From 2nd and 3rd equation]

From these equations we get
16x+4y-6x-4y=82-4316x+4y6x4y=8243
=>x=3.9x=3.9
Similarly we get the value of y=(41-8xx3.9)/2=4.9y=418×3.92=4.9

Thus we can determine the value of the radius of the circle...
sqrt((3.9-2)^2+(4.9-2)^2)=2.1 unit(3.92)2+(4.92)2=2.1unit (approx)
Hence the area of the circle is pixxr^2=13.86 unit^2π×r2=13.86unit2 (approx)