Question

how do we graph this ?? Any help would be awesome! 16 less than or equal to x2+ y2 less than or equal to 25

Answer 1

x^2+y^2=r^2 is a circle remember?

Answer 2

a donut centered at the origin inner radius 4 outer one 5

Answer 3

maybe torus?

Answer 4

spare tire?

Answer 5

i was fixing to say that
and then shade on the donut

Answer 6

concentric circles?

Answer 7

do not shade the donut hole

Answer 8

no save that for me!

Answer 9

just the donut

Answer 10

awesome how do you know its a circle

Answer 11

because (x-h)^2+(y-k)^2=r^2 is the general form for the a circle

Answer 12

pythagoras.
\[x^2+y^2=r^2\] says distance between (0,0) and (x,y) is r