Diameter of a circle endpoints P(0,0) Q(8,-4) what equation:

  • Thread starter Thread starter Jaco Viljoen
  • Start date Start date
  • Tags Tags
    Circle Diameter
Click For Summary
The diameter of the circle with endpoints P(0,0) and Q(8,-4) is determined by first calculating the midpoint, which is M(-4,-2). The radius is then found using the formula r²=(x-h)²+(y-k)², resulting in r²=20. Consequently, the equation of the circle is (x-4)²+(y+2)²=20. The discussion also highlights the appropriate categorization of the problem under analytic geometry in the Precalculus section. This provides a clear method for finding the equation of a circle given its diameter endpoints.
Jaco Viljoen
Messages
160
Reaction score
9
Mod note: Moved from technical math section, so no template.
The diameter of a circle has endpoints P(0,0) and Q(8,-4) Find the equation:

First I will find the midpoint:
M(x,y)=(x1+x2)/2,(y1+y2)/2
=8/2,-4/2)
M(x,y)=(-4,-2)

Then I will find the radius:
r^2=(x-h)^2+(y-k)^2
r^2=(0-4)^2+(0+2)^2
r^2=16+4
r^2=20

so
(x-4)^2+(y+2)^2=20
 
Last edited by a moderator:
Physics news on Phys.org
Jaco Viljoen said:
The diameter of a circle has endpoints P(0,0) and Q(8,-4) Find the equation:

First I will find the midpoint:
M(x,y)=(x1+x2)/2,(y1+y2)/2
=8/2,-4/2)
M(x,y)=(-4,-2)

Then I will find the radius:
r^2=(x-h)^2+(y-k)^2
r^2=(0-4)^2+(0+2)^2
r^2=16+4
r^2=20

so
(x-4)^2+(y+2)^2=20
That's what I get, as well.

BTW, this looks like homework, or at least a problem from a textbook, so I'm moving it to the homework section.
 
  • Like
Likes Jaco Viljoen
Thank you Mark,
I wasn't sure if I should post under pre calculus as I couldn't find any geometry there, thanks again.
 
This would come under the heading of analytic geometry, so the Precalc section is the right place for it.
 
  • Like
Likes Jaco Viljoen

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
Replies
4
Views
2K
Replies
1
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 62 ·
3
Replies
62
Views
10K
Replies
5
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K