How do you write an equation for for circle given that the endpoints of the diameter are (-2,7) and (4,-8)?
2 Answers
Explanation:
"given the endpoints of the diameter then the centre is at"given the endpoints of the diameter then the centre is at
"the midpoint and the radius is the distance from the "the midpoint and the radius is the distance from the
"centre to either of the 2 endpoints"centre to either of the 2 endpoints
"the equation of a circle in standard form is"the equation of a circle in standard form is
color(red)(bar(ul(|color(white)(2/2)color(black)((x-a)^2+(y-b)^2=r^2)color(white)(2/2)|)))
"where "(a,b)" are the coordinates of the centre and r "
"is the radius"
"midpoint "=[1/2(-2+4),1/2(7-8)]=(1,-1/2)
"to calculate the radius use the "color(blue)"distance formula"
•color(white)(x)d=sqrt((x_2-x_1)^2+(y_2-y_1)^2)
"let "(x_1,y-1)=(4,-8)" and "(x_2,y_2)=(1,-1/2)
d=sqrt((1-4)^2+(-1/2+8)^2)
color(white)(d)=sqrt(9+225/4)=sqrt261/2
(x-1)^2+(y+1/2)^2=(sqrt261/2)^2
rArr(x-1)^2+(y+1/2)^2=261/4larrcolor(blue)"equation of circle"
Therefore, equation of the given circle is
Explanation:
Center coordinates
diameter /2 = radius =
Standard equation of a circle is
Therefore, equation of the given circle is