Question 75525
the first circle has a area of {{{25pi}}}...since {{{area=pi*r^2}}}...{{{r^2=25}}}... and r=5


the second circle has a circumference of {{{3pi}}}...since circumference={{{2pi*r}}}...r=3/2...or r=1.5


the radius of the third circle is the distance from the center (2,1) to a point on the circumference (6,4)...the expression for this distance is {{{sqrt((6-2)^2+(4-1)^2)}}}...which evaluates to {{{sqrt(25)}}}... so r=5



equation 1...{{{(x-5)^2+(y+3)^2=25}}}


equation 2...{{{(x+2)^2+(y-7.5)^2=2.25}}}


equation 3...{{{(x-2)^2+(y-1)^2=25}}}