Question

(-3,4) is a point on the circle with centre at origin.

a) what is radius of the circle?

b) Does (-4,2) lie interior to the circle? Why?​

Answer 1

Step-by-step explanation:

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,

Answer 2

R=root of -3^2+4^2=9+16 =root25=5
D=1^2+2^2 root5
So (-4,2) lie inside the circle