Question

circle with center (-1 2) passes through point (2 -2). which is true?
A. the radius is square- root of 5
B. the diameter is 10.
C. the equation is (x+1)^2 + (y-2)^2 = 10.
D. the circumference is 25x.

Answer 1

Radius of this circle is 5, so the diameter will be 10 :) B is correct

Answer 2

This is because to calculate the radius we do (difference in x coordinates)^2 + (difference in y coordinates)^2 = radius^2

Answer 3

Its sort of pythagoras theorem again :)

Answer 4

okay thank you. i have one more question if thats okay?

Answer 5

Yes.

Answer 6

By the way, the equation for this circle will be (x+1)^2 + (y-2)^2 = 25

Answer 7

it says which equation of a circle with diameter segment AB with A(5,4) and B (-1,-4)? how would i do that?

Answer 8

Well my english is not perfect, but what i understand by diameter is just radius twice :).

Answer 9

Do you think that the center of the circle will be the midpoint between A and B? :)

Answer 10

Then,if you know how to calculate midpoints, you can find the center of the circle.
Once you have the center of the circle and some point on the circle (A or B), you can find the equation for the circle right? :)

Answer 11

calculate midpoint?