Question

What is the standard form of the equation of a circle whose diameter is 20 units and whose center is (−1,7)?

Answer 1

Answer:

$(x + 1)^2 + (y - 7)^2 = 100$

Step-by-sep explanation:

Given:

Diameter of circle = 20 units

Center of circle = (-1, 7)

Standard form of the equation of a circle is expressed in the center-radius form as:

$(x - h)^2 + (y - k)^2 = r^2$,

Where,

h = -1

k = 7

r = ½ of diameter = ½(20) = 10 units

Plug in the values into the equation

$(x - h)^2 + (y - k)^2 = r^2$

$(x - (-1))^2 + (y - 7)^2 = 10^2$

$(x + 1)^2 + (y - 7)^2 = 100$