Question

The equation of a circle is given below.

(x - 5)² + (y + 2)² =81/4
What is its center?
What is its radius?
If necessary, round your answer to two decimal places.
units

Answer 1

Emily, use the circle formula to solve this (x−a)^2 + (y−b)^2 = r^2

Explanation:

where a and b are the center off sets in the x and y directions , repspectively.

(x - 5)² + (y + 2)² =81/4

So you now know, the center is at (x,y) = ( 5, 2)

and the radius is
`\sqrt{(81)/(4) }` , why is is square rooted ? you ask.

because in our formula above it's r^2 .. so we need to square root it to find it's value.

`(√(81) )/(√(4) )` =
`(9)/(2)` = 4.5 rounded to two decimals 4.50 but not necessary