Question

Points A(-l, y) and B(5,7) lie on a circle with centre 0(2, -3y). Find the values ofy.
Hence, find the radius of the circle.

Answer 1

Answer:

may be my answer helps you

Step-by-step explanation:

a. What is the radius of the circle?

b. If a point in the circle is (x, y), write the relation between x, y?

c. Check whether the point (-2,1) lie on this circle.

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ANSWER

Given, centre (3,4); Orgin (0,0)

a. Radius (r)=

x

2

+Y

2

(formula)

=

3

2

+4

2

=

9+16

=

25

=5.

b. Equation of the circle

=(x−a)

2

+(y−b)

2

=r

2

.

ie., (x−3)

2

+(y−4)

2

=5

2

.

⇒x

2

−6x+9+y

2

−8y+16=25

⇒x

2

+y

2

−6x−8y+25−25=0

⇒x

2

+y

2

+6x+8y=0

be the equation of the circle,

c. (-2,1), put this value in the equation

we get, (−2)

2

+(1)

2

−6x−2−8×1=0

4+1+12−8=0

17−8=0

9



=0

Hence, the point (-2,1) is not lies on the circle.

solution