Question

4. Determine the center and radius of each circle.

Answer 1

a) Center (0,0) and radius 5

b) Center (-1,-2) and radius 2.236

c) Center (2,9) and radius 4    

Step-by-step explanation:

Equation of circle with (h,k) as center and radius r is given by,

          (x-h)²+(y-k)² = r²

a) 3x²+3y²=75

   Dividing by 3

                    x²+y²=25

                    (x-0)²+(y-0)² = 5²  

          Center (0,0) and radius 5

b) 2(x+1)²+2(y+2)²=10

 Dividing by 2

        (x+1)²+(y+2)²=5

        (x-(-1))²+(y-(-2))²= 2.236²

          Center (-1,-2) and radius 2.236

c)  4(x−2)²+4(y−9)²−64=0  

           4(x−2)²+4(y−9)²= 64

 Dividing by 4

          (x−2)²+(y−9)²= 16

          (x−2)²+(y−9)²= 4²

          Center (2,9) and radius 4