Question

help please !!! find the equation for the circle that satisfies the conditions

5) center at the origin passes through (4,7)

Answer 1

do you know the distance formula?

Answer 2

no

Answer 3

distance between origin (0,0) and (x,y)=(4,7)
\[\sqrt{x^{2}+y ^{2}}\]

Answer 4

do u find radius = distance between origin and the point

Answer 5

is midpoint formula needed here

Answer 6

@marcelie do you need a help?

Answer 7

yes

Answer 8

okay. then

Answer 9

now first find radius.

radius^2 = (4-0)^2 + (7-0)^2= 16+49 = 65
\[radius = 65^{1/2}\]

Answer 10

now you have to know , there is a theorem to find formula of a circle with radius

Answer 11

it is
x^2 + y^2 = radius^2

Answer 12

so the answer is
x^2 + y^2 = 65

Answer 13

is midpoint formula needed ?

Answer 14

no. you don't need to find midpoint for that. you need to know radius. that's it. wait , I will send you references

Answer 15

http://www.regentsprep.org/regents/math/algtrig/atc1/circlelesson.htm

here it is

Answer 16

look at the diagram at left side on that page.

Answer 17

hope that helps. bye

Answer 18

wait..

Answer 19

how come on number five here they used midpt o.o

Answer 20

http://www.personal.kent.edu/~bosikiew/Algebra-handouts/circles.pdf

Answer 21

it is difference. nothing has to do with this problem

Answer 22

ah ok

Answer 23

look closely, on number 5, they don't say center is (0,0)

Answer 24

(0,0) is on the curve line of circle

Answer 25

but in our problem, (0,0) is the center. get it?

Answer 26

bye

Answer 27

the problem u asked is different from the example one

Answer 28

@lochana
ur solution is right

Answer 29

yes. he confused center and origin. that's why he had that problem i guess