1. ## [SOLVED] Coordinates (549)

In the xy-plane, the center of a circle has coordinates (3, -7). If one endpoint of a diameter of the circle is (-2, -7), what are the coordinates of the other endpoint of this diameter?

2. (8,-7) (HINT: Look at the y value of the given coordinates)

3. Is it because both paired coordinates are -7, so the answer is -7? But how did you get the 8 from (8, -7)?

4. Originally Posted by fabxx
In the xy-plane, the center of a circle has coordinates (3, -7). If one endpoint of a diameter of the circle is (-2, -7), what are the coordinates of the other endpoint of this diameter?
Let the co-ordinate of other endpoint be $(x_1, y_1)$

Since, diameter connects these two end-points, so the center is midpoint of these two endpoints.

According to mid point formula,

$(3, -7) = \left(\frac{-2+x_1}{2}, \frac{-7+y_1}{2} \right)$

$\Rightarrow x_1=8,\;\;y_1=-7$

Did you get it now???