Question
A circle on the Coordinate plane has a diameter with endpoints at (6,8) and (15,8). What are the coordinates of the center of the circle? What is the radius of the circle? Identify the coordinates of another point on the circle. Explain how you found your answer.
Answers
midpoint of diameter
= ( (6+15)/2 , (8+8)/2)
= ( 21/2 , 8)
equation:
(x-21/2)^2 + (y-8)^2 = r^2
plug in (6,8)
81/4 + 0 = r^2
(x-21/2)^2 + (y-8)^2 = 81/4
any other point?
how about the y-intercept, let x = 0
441/4 + (y-8)^2 = 81/4
y-8 = ±√90 = ±3√10
y = 8 ±√10
so (0, 8+3√10) and (0,8-3√10) are two more points
= ( (6+15)/2 , (8+8)/2)
= ( 21/2 , 8)
equation:
(x-21/2)^2 + (y-8)^2 = r^2
plug in (6,8)
81/4 + 0 = r^2
(x-21/2)^2 + (y-8)^2 = 81/4
any other point?
how about the y-intercept, let x = 0
441/4 + (y-8)^2 = 81/4
y-8 = ±√90 = ±3√10
y = 8 ±√10
so (0, 8+3√10) and (0,8-3√10) are two more points
Related Questions
A diameter of circle that has endpoints (-4,12) and (8,-2), as shown below, is in the standard (x,y)...
The endpoints of the diameter of a circle are (-6,2) and (10,-2). What are the coordinate of the cen...
Points A(3,5) and B(7,10) are the endpoints of a diameter of a circle graphed in a coordinate plane....
in the coordinate plane, the points (2,2) and (2,12) are the endpoints of a diameter of a circle. wh...