Question

What is the equation of a circle with center (3,8) and radius 2?

A. (X+3)^2 + (y+8)^2=4
B. (X-3)^2 + (y-8)^2=4 <--- my answer
C. (X+3)^2 + (y+8)^2=2
D. (X-3)^2 + (y-8)^2=2

Answer 1

hint:
we have to apply the definition of a circumference, namely:
"the set of all points of the plane such that the distance, from the center, is equal to the radius of such circumference"

Answer 2

Ok..

Answer 3

So my answer is wrong

Answer 4

it is right!

Answer 5

K good thanks

Answer 6

since, the distance of a point p=(x,y) from the center C=(3,8) is:
\[d = \sqrt {{{\left( {x - 3} \right)}^2} + {{\left( {y - 8} \right)}^2}} \]
and that distance, has to be equal to the radius of your circumference, namely 2

Answer 7

thanks!

Answer 8

👍