Hi there i'm in highschool doing my second to last year 
I was working through a text book and i got this question:
A circle, centre (0,0) has a diameter of 7 units long. Write down the equation of this circle. Make sure the equation has whole-number coefficients, can someone please explain to me how to do this questions? I'm having a hard time getting my head around circle graphs. Can anyone explain to me, or hint me how to workout this question? i've done x^2+y^2=49 but i'm not sure if i need to put numbers in front of the x^2 and y^2 to manipulate the circle.
Thank you in advance,
I was working through a text book and i got this question:
A circle, centre (0,0) has a diameter of 7 units long. Write down the equation of this circle. Make sure the equation has whole-number coefficients, can someone please explain to me how to do this questions? I'm having a hard time getting my head around circle graphs. Can anyone explain to me, or hint me how to workout this question? i've done x^2+y^2=49 but i'm not sure if i need to put numbers in front of the x^2 and y^2 to manipulate the circle.
Thank you in advance,