Inscribed Angle, Circle EquationDate: 6/14/96 at 14:58:44 From: Anonymous Subject: Inscribed angle, circle equation What's an inscribed angle? What's the equation for the center of the circle of (8,-1) with radius 15? Date: 6/19/96 at 14:53:47 From: Doctor Paul Subject: Re: Inscribed angle, circle equation Let's first talk about inscribed angles.. Here's the dictionary definition: to draw within a figure so as to touch in as many places as possible (a regular polygon inscribed in a circle). So... to inscribe an angle in a circle, put the vertex at one point on the circle and make sure that the rays leading away from the vertex also touch the circle (at places other than the vertex, of course). I think you misphrased the second question. Here's what I think you meant to ask: What is the equation of the circle with center (8,-1) and radius 15? To do this problem you need to know the formula. Here it is: (x-h)^2 + (y-k)^2 = r^2 where (h,k) is the center and r is the radius. In your specific case, h is 8, k is -1, and r is 15 to complete the problem, just plug h, k, and r into the equation I gave you above.. (x-8)^2 + (y-(-1)^2 = 15^2 now recall that subtracting a negative number is really adding... so y-(-1) is really y+1 (x-8)^2 + (y+1)^2 = 225 It would be perfectly okay to expand this out, but equations of circles are usually left in this form because it is much easier to tell what the coordinates of the center and the radius of the circle are. -Doctor Paul, The Math Forum Check out our web site! http://mathforum.org/dr.math/ |
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